HALT & HASS - when and how is it relevant? An introduction to HALT & HASS focusing on classical HALT Susanne Otto, DELTA

Photo of the jet by Fototjenesten, Flyvestation Ålborg

June 2004

SPM's sekretariat DELTA Dansk Elektronik, Lys & Akustik Venlighedsvej 4 DK-2970 Hørsholm Telefon: 72 19 40 00 Fax: 72 19 40 01 www.delta.dk/spm

Sammenslutningen for Pålideligheds- og Miljøteknik

SPM-169

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SPM

Society for Reliability and Environmental Testing SPM is an independent organisation consisting of about 100 company members in Scandinavia.

SPM initiates and finances unprejudiced investigations of common interest for its members – mainly in the field of reliability and testing of electronic components and materials.

NOTE: The report must not be reproduced without the written approval of the Society for Reliability and Environmental Testing (SPM).

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Table of contents 1. Summary..................................................................................................................... 4 2. Introduction................................................................................................................ 5 2.1 Purpose of the project .................................................................................................. 5 2.2 The outline of the project ............................................................................................. 5 2.3 Introduction to HALT & HASS................................................................................... 6 3. HALT & HASS in comparison with conventional test strategies.......................... 9 3.1 Characterisation of tests ............................................................................................... 9 3.2 Test specimen............................................................................................................... 9 3.3 Test conditions ........................................................................................................... 11 3.4 Monitoring of test specimen ...................................................................................... 13 3.5 The new tests.............................................................................................................. 13 3.6 Conventional tests ...................................................................................................... 17 3.7 Test matrix - overview ............................................................................................... 26 3.8 Comparison of conventional and new tests................................................................ 26 4. Failure analysis – an important tool....................................................................... 29 4.1 Failure analysis – Conventional and in relation to HALT ......................................... 29 5. Case studies............................................................................................................... 35 5.1 DC/DC converter supplied by Terma A/S for use in aircrafts ................................... 37 5.2 Adapto BTE (Behind The Ear) hearing aid supplied by Oticon A/S......................... 47 5.3 Ultrasound scanner electronics from B-K Medical A/S ............................................ 55 5.4 Modules for BeoSound 1 and BeoSound 3000 from Bang & Olufsen A/S............... 68 6. Survey of results ....................................................................................................... 82 7. Guidelines ................................................................................................................. 83 7.1 Guideline for introduction of HALT & HASS .......................................................... 83 7.2 Guideline for selection of HALT exposures .............................................................. 86 7.3 Guideline for design of HASS cycle.......................................................................... 88 8. Discussion and conclusion ....................................................................................... 90

Annex 1 Literature references ……………………………………………………….92

Annex 2 DELTA HALT facilities ………………………………………………......95

Annex 3 Case study - DC/DC converter for use in jet fighters supplied by Terma A/S - detailed test log, “Cooling of power module”, vibrations tests performed according to MIL-STD-810F …………............98

Annex 4 Case study - CQ-6263 Adapto BTE hearing aid supplied by Oticon A/S - detailed test log ………………………………………….....106

Annex 5 Case study - Ultrasound scanner 2120 EXL supplied by B-K Medical A/S - detailed test log ……………………………………...115

Annex 6 Case study – Modules for BeoSound 1 and BeoSound 3000 supplied by Bang & Olufsen A/S – detailed test log……………………147

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1. Summary HALT & HASS is an exciting new test philosophy which has gained great interest from a large number of companies in Scandinavia within the last couple of years. Some companies have already performed HALT while others are still discussing whether it is relevant to perform a HALT.

These companies are faced with the question on when and how HALT & HASS is relevant for them.

The project gives an introduction to HALT & HASS by describing the test strategies and relating them to other test and analysis strategies. However, the main focus is on the practical part demonstrating the application of HALT on a number of different products for very different applications. The presentation of the cases includes all practical aspects of a HALT e.g. criteria for selection of test specimen, function test and function test set-up, selection of HALT exposures, fixation of test specimen, summary of testing and results as well as comments and conclusion. The majority of the cases has involved classic HALT i.e. HALT with thermo-mechanical exposures. The conclusions drawn from the case studies have lead to the formulation of guidelines regarding implemen-tation of HALT & HASS, selection of HALT conditions and design of a HASS cycle from HALT results.

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2. Introduction

2.1 Purpose of the project

HALT & HASS is an exciting new test philosophy which has gained great interest from a large number of Scandinavian companies within the last couple of years. Some companies have already performed HALT while others are still discussing whether it is relevant to perform a HALT.

These companies are faced with the question on when and how HALT & HASS is relevant for them. They need answers to the following questions:

• What is there to gain from HALT & HASS?

• How do HALT results compare to field failures?

• How does HALT & HASS fit in with other test and analysis method?

• Which HALT & HASS exposures are relevant?

• How to come from HALT to HASS?

• How to get started?

The purpose of this project is to give these companies an input to decision making on when and how HALT & HASS is relevant for their product and the company by answering these questions.

2.2 The outline of the project

This project gives an introduction to HALT & HASS by describing the test strategies and relating them to other test strategies. Further, a description of failure analysis in relation to HALT is given.

However, the main focus is on the practical part demonstrating the application of HALT on a number of different products for very different applications. The presentation of the cases includes all the practical aspects of a HALT e.g. criteria for selection of test speci-mens, function test and function test set-up, selection of HALT exposures, fixation of test specimen, summary of testing and results as well as comments and conclusion. The majority of the cases have involved classic HALT i.e. HALT with thermo-mechanical exposures. However, also bounce and sweat exposures have been included. The conclusions drawn from the case studies have lead to the formulation of answers to the questions asked initially.

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Thus the project falls into three parts:

1) The theoretical part where HALT & HASS is described and related to a number of other test and analysis strategies.

2) Case studies demonstrating HALT in practical terms on test specimens supplied by SPM-members and the HALT/HASS ERFA-group in particular.

3) Formulation of guidelines regarding implementation of HALT & HASS, selection of HALT conditions and design of a HASS cycle from HALT results.

2.3 Introduction to HALT & HASS

HALT (Highly Accelerated Life Testing) and HASS (Highly Accelerated Stress Screening) are an interesting test philosophy originally developed in the US by Gregg Hobbs some 30 years ago. It has finally spread and gained support in Europe over the last 5 - 10 years.

HALT & HASS find and rectify potential failures in products at the earliest possible stage. The result is more reliable products, more satisfied customers, reduced warranty and service costs and shorter time-to-market.

HALT is a research and development tool, which efficiently points out the failures related to the design of the product. Whereas HASS is a tool for pointing out the failures related to the production process.

HALT is not a means of predicting actual life time for products even if “Life” form part of HALT. It would be more appropriate for HALT to be an acronym for Highly Accelerated Limit Testing. However, that is not the way it is.

During HALT the product is exposed to a number of test conditions selected based on the relevant failure mechanisms of the product. There is no “standard” procedure. Typical conditions or classic HALT conditions are extremely high and low temperatures, fast temperature change (up to 60ºC/min. measured on the product), vibration and temperature change combined with vibration. However, voltage variations, humidity, shocks and combinations of humidity and temperature as well as any other conceivable condition leading to relevant failures may be utilised. The product is exposed to the conditions or combination of these in steps of increasing stress. The stress level is increased in steps well beyond specification limits of the product.

Efficiency is achieved by testing at extreme levels. In this way, failures are detected within few hours rather than after weeks of traditional testing or several years in the field. The test conditions are in no way intended to simulate the use environment.

The function of the product is constantly monitored, failures are detected and analysed. The stress level at which failure occurs is of no relevance. The only interesting point is

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whether the failure mechanism is relevant or not. In case the failure is relevant it should be corrected.

HASS testing procedure is designed on the basis of the limits identified by HALT. A typical procedure consists of rapidly induced temperature transitions combined with 6-axis vibration. Tests are of short duration – ideally lasting just a few minutes. It is critical to ensure sufficient lifetime remaining in the product after screening, and that all induced failures are identified. Otherwise the end customers will discover them later.

Failure analysis on the failed samples is an important component of HALT & HASS in determining whether a given failure is relevant. An appreciation of the mechanism behind the failure increases the chances of choosing the right solution. Failure analysis can also reveal failures not found by the functional screening process.

It is the HALT & HASS process i.e. the testing in combination with failure analysis and the improvement process that results in enhanced products, see fig. 2.1 below.

FIG. 2.1 The HALT & HASS process.

HALT is seen as a supplement to conventional qualification testing.

The benefits of HALT & HASS are:

• Huge savings in warranty and service costs

• Shorter time-to-market

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• Confidence and insight when introducing new products

• Large and known strength margins to operational stress

• Possibility of investigating field failures

• Product is mature and free from teething troubles when entering production

• Reduced rework in production

• Failures practically never occur when product is in use

• Customer requirements satisfied

Originally HALT & HASS was used for high volume products or small volume and high value products. Now, all types of product developing companies will gain benefit from HALT & HASS. A number of technologies and industries are already employing HALT & HASS. These include space technology, the military, aviation, telecommunication, information technology, medico, automotive, sensor devices, measuring and electronic control devices.

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3. HALT & HASS in comparison with conventional test strategies

3.1 Characterisation of tests

The conventional universe of tests is described here in order to serve as basis for a comparison with the new tests, HALT & HASS.

The description of the tests considers the following subjects:

• Test specimen

• Test conditions

• Monitoring of test specimen

3.2 Test specimen

The types of product considered are equipment type products or subassemblies of such products. This means end-user products or functional modules thereof made of electrical, mechanical, electromechanical or electronic hardware. These products usually have a high degree of complexity, which also makes testing them rather complex. Microelectronics and microsystems are included, but discrete semiconductors and components like resistors, capacitors and networks are excluded.

How the actual items of the product are selected for test depends on the purpose of the test. Different selections characterised according to the stage in the creation process are described in the following sections.

3.2.1 Development samples

The product may be tested in its very early stage of development. The objects tested range from breadboards to fully functional mock-ups. The purpose of such tests may be to check the capability of principal solutions, circuit details or structural details to yield questionable parts of the product’s intended performance. Test in this phase is an iterative process alternating with the design activities. The test conditions in this phase are normally focused on those critical for the performance parameter in question. The monitoring may be anything from simple check of survival to detailed measurements.

3.2.2 Prototypes

A step further in the development process, the product design has been defined and the first physical realisations made. A substantial part of its circuits and structural parts is typically handmade without the final tooling. The purpose of test in this phase is to obtain a complete picture of all aspects of the product's performance in all situations of its life in use. The test conditions in this phase are often contractually defined and they intend to cover all situations of the product life. The monitoring is designed to cover all

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functional and survival parameters. This kind of test is often referred to as “qualification test”, “type approval test” or “design verification test”.

3.2.3 Pilot production items

At this step of development, not only the product, but also the manufacturing process is defined, and the first product samples are made using the final tooling and the final production processes. The traditional purpose of test in this phase is to make sure that no part of the product’s performance has been lost during the transformation from development to production. The test conditions and the monitoring are often a subset of those from the prototype test. As integrated product development is now more and more common that the production processes are developed parallel to the product design, and the transition from prototype to pilot production item becomes gradual. This kind of test may also be contractually defined and serve as criterion for start of delivery.

3.2.4 All production items

The performance of the production items is a function of the ingoing materials and components. These elements may be checked for defects before entering the production process, but according to the circumstances also, or alternatively, after some of the production process steps. This calls for a simple functional test without environmental stress. Another reason for test at this step is to speed up the production maturing process. After the completion of the development of the product and the production processes, the production processes will normally not be perfectly implemented right from the beginning. Typically they mature during the first period of production and the product quality gradually becomes better. In order to facilitate this maturing process, all manufactured items may be tested in a screening process. The test conditions will be focused on those able to reveal latent defects introduced by inadequate production processes. The monitoring is designed to detect the failures originating from the latent defects precipitated as patent defects. Since the test conditions involve environmental stress, this kind of test is often referred to as “environmental stress screening”. Another name is “burn in”, because an early form of the test involved heat as the sole environ-mental stress.

3.2.5 Production items according to sample plan

The production process is subject to change due to influence from many sources. These changes may be intentionally introduced or they may just happen without notice. Any kind of tests as described above in sections 3.1.2 through 3.1.4 will therefore be useful as part of the production control tool to keep the process on track when performed on samples of running production. The test conditions can be anything from zero stress to accelerated stress. The monitoring may be concentrated on a few carefully selected indicator parameters, however, it will normally be focussed on key operational parameters.

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3.3 Test conditions

The test conditions are a combination of the functional conditions of the product, the environmental conditions and the time. Although not completely independent, these 3 elements can be said to make up the 3 dimensions of test conditions.

3.3.1 Reference test

A reference test is a test with emphasis on attributes concerning functional input and output parameters. The purpose of a reference test is to obtain a measure for the functional capability or performance of the product. It may be made under ideal zero-stress conditions in order to obtain a measure for the best possible product performance. (By zero-stress is meant no other stresses than induced by the functional parameters themselves). It may also be made during or between exposures of an environmental or endurance test (see sections 3.3.2 and 3.3.3 below). Reference test can be considered as a 1-dimensional test.

3.3.2 Environmental test

An environmental test is a test with emphasis on a product’s ability to maintain a wanted functional attribute when exposed to environmental stress. The traditional philosophy is to consider stress levels so high that the probability of reaching or exceeding them in actual use is low. Anyhow, the levels are not substantially exceeding those which could occur. Since the probability of 2 or more environmental stress types reaching this high level at the same time is extremely low, this kind of test is usually made by exposing the product to 1 environmental parameter at a time. Since these high levels of environmental stress do not occur very often, the duration connected to their occurrence is considered to be short. The time for the product to be exposed to each environmental parameter during test is therefore also relatively short. It is usually set to somewhat longer than judged to be necessary in order to reach stable conditions.

Some environmental parameters are known to produce special effects when applied in combination. The classic example is condensation of water and water accumulation in hollow spaces caused by high relative humidity in combination with change of temperature. Even in these cases, the test time is related more to obtaining the special effects looked for than to obtain some kind of simulation of duration-related phenomena of the use period.

In other words, environmental test provides information of a product’s ability, in condition as new, to maintain a wanted attribute when exposed to expected environmental stress. The attributes are monitored by functional tests before, during and/or after the environmental exposure. Environmental test can be considered as a two-dimensional test.

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3.3.3 Endurance test

An endurance test is a test with emphasis on the product’s ability to maintain a wanted attribute during time combined with all kinds of stresses occurring from operation, manipulation and environment. The effect of these stresses is an accumulation in time of damage to the product. If the accumulated damage reaches a sufficiently high level, the product fails. Endurance test can be performed straight away by just using the product. This means non-accelerated endurance test. Since this leads to a test time comparable to the real intended product life, it is desirable to obtain some kind of acceleration. To this effect, the test exposures may be time-accelerated or stress level accelerated. Both methods contain large uncertainties, however, it should be kept in mind that the acceleration factor established by either method refers to some normal use conditions, which themselves are rather difficult to define precisely. Endurance test can be considered as a 3-dimensional test.

3.3.3.1 Non-accelerated endurance test

This kind of test has the very great advantage that it can be performed as a field test in real use environment and by real users. It therefore requires little or no analysis of use conditions, design of test conditions and complex test equipment. The long test time, however, is a major drawback, and makes the test little useful.

3.3.3.2 Time-accelerated endurance test

During the life of a product, it will meet a complex stress situation made up of many types of stress. These stresses can be described by a number of environmental and operational parameters acting in combination. The levels and combinations of these parameters vary over time. Due to this variation, the time history will in most cases contain periods of time where the stress levels are low compared to other periods where stress levels are high. During periods of high stress, the accumulation of damage takes place at a higher rate than during periods of low stress. Time acceleration can thus be achieved by neglecting the periods of low stress where the damage accumulation is insignificant. The stress levels of the remaining periods are then reproduced in the test conditions with representative severities and combinations. Since it is normally important to know the point of time when the test item eventually fails, the test environment is designed to reproduce small portions of product life at a time. These small portions - test cycles - are then repeated several times. The acceleration factor obtainable by this method is typically limited to 5 - 20 times. This is the most important drawback of this method.

3.3.3.3 Stress level accelerated endurance test

If the accumulation of damage due to the effect of all environmental parameters involved - separately and in combination - is known as a function of time and stress level, stress level acceleration is useful. First, the accumulated damage during a normal product life is

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calculated by integration for all stress parameters - alone and in combination - calculating the summation of differentials of damage accumulation multiplied with differentials of time. Then, a test condition with accelerated stress levels is selected, which - by the same calculation - gives the same damage accumulation in the desired shorter time. A number of empirical formulas giving the relationship between damage accumulation rate and parameter severity exist (see ref. [16] section 7.2 and ref. [17] chapter 2). They are all of exponential type, so that an additive increment of stress level corresponds to the multiplication of damage accumulation rate by a factor. The acceleration factor obtainable by this method can be very high. The drawback is that it requires a very detailed knowledge of the product and its failure mechanisms. Otherwise the choice of acceleration function is pure guesswork.

3.4 Monitoring of test specimen

The attributes to be monitored and the method of monitoring depend on the details of the actual test and the product tested, especially the attributes, for which information is sought. The more principal considerations are related to the continuity or time of monitoring. This is generally done in 2 ways:

1) Monitoring before and after exposure is used when the only information desired is the permanent effect of the test condition on the test specimen. In other words, whether the test specimen has suffered permanent damage from the test condition.

2) Monitoring during exposure is used when the information desired relates to a temporary effect of the test condition on the test specimen. In other words, whether the test specimen has exceeded some operating limit due to the test condition.

3.5 The new tests

HALT

The acronym stands for Highly Accelerated Life Test (see ref. [16]: "Accelerated reliability engineering. HALT and HASS". Gregg K. Hobbs. Wiley & Sons Ltd, 2000; and ref. [17]: "HALT, HASS & HASA Explained. Accelerated Reliability Techniques." Harry W. McLean. American Society for Quality, 2000). It is a test technique that evolved around 1970 at Hewlett-Packard under the names “Design Ruggedization” and STRIFE (STRess plus lIFE).

The idea is simple: Apply stresses to a product in excess of its design specification to generate failures, find the root cause of each failure and eliminate them by design improvements. When this is done during the original design of the product, it will result in a much more reliable product.

The basic idea has appeared under different names: DOE (Design Of Experiments) has been used by Motorola in support of their well known 6 sigma concept. Other acronyms appearing are TAF (Test Analyse and Fix) and RGT (Reliability Growth Test).

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The background philosophy for this kind of test is entirely different from the traditional test philosophy.

Traditionally, test is seen as a measurement instrument to measure some quality para-meters of a product (either a value or go/no-go). In order to optimise this measuring instrument, the focus has been on the ability of test methods to detect the intended quality parameter and obtaining a measure for it with reasonable accuracy and reproducibility without spending too much time and money.

HALT, however, is a tool to improve the quality of a product by finding and eliminating weak points, both in the design and in the production processes. This process of improving is iterative. It stops when margins between breakdown limits and operating conditions are the largest reasonably possible. In order to optimise this tool, the focus is on finding the weak points relevant for real use and introduce redesign or process change to eliminate them without spending too much time and money.

This changed philosophy implies:

1) The test must find operation limits and destruction limits. The stress levels for each parameter and combination of parameters are therefore successively increased until, first: cease of operation, second: permanent destruction.

2) When one limit of a certain stress parameter or a combination has been identified, the test must go for the next higher limit of the same. This continues until failure analysis (4) indicates that failures are irrelevant. In order to do this, the foregoing failures can be temporarily fixed by replacement and protection of parts.

3) Combinations of environmental stress parameters must be used because they are more destructive than one parameter at a time. Extreme temperature and temperature change are therefore combined with random vibration (all frequencies at the same time) and 6-axis excitation (3 translations and 3 rotations at the same time).

4) All failures must be analysed and the following questions answered: A: Is it possible that it could happen in real use? B: How can its root cause be eliminated?

5) The root cause for all failures for which answer A is “yes”, has to be eliminated according to answer B. The margin between the product specification limit and in the first hand the operation or destruction limit shall not be considered. The purpose of the HALT process is to extend these limits as far as possible.

6) The HALT process continues until the failure analysis (4) shows that the failures precipitated are irrelevant for real use and fundamental limits of the involved materials processes and technologies are approached.

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7) When the root cause of all relevant failures has been eliminated by proper design and process corrections and these changes are implemented, a re-HALT will be appropriate. If this re-HALT shows persisting problems due to inadequate corrections, another re-HALT may be necessary. The process does not stop until sufficiently great margins (6) have been achieved.

The fact that HALT is aiming on improving products instead of measuring their performance implies that it concentrates more about analysing the relevance of failures than considering the relevance and reproducibility of stress exposures. It is of no importance how a failure occurs, however, it is extremely important if the same failure might occur in real use.

Both ref. [16] and [17] describe a possible theoretical choice of a number of different types of stress exposure. When it comes to the descriptions of the practical performance of HALT, the choice narrows to extreme temperature, fast change of temperature and vibration.

Since the main focus is on failures, failure analysis is very important. You could say that the lack of reproducibility has been replaced by analysis of failures for relevance. Expedient and accurate failure analysis is essential for the successful management of HALT.

HASS

The acronym stands for Highly Accelerated Stress Screening. Ref. [16]: "Accelerated reliability engineering. HALT and HASS". Gregg K. Hobbs. Wiley & Sons Ltd, 2000; and [17]: "HALT, HASS & HASA Explained. Accelerated Reliability Techniques". Harry W. McLean. American Society for Quality, 2000.

Also this idea is simple: The field reliability of a product can be improved by finding and removing the weakest members before they are shipped.

The basic idea appeared already between 1950 and 1960 under the name “burn-in” and was later referred to as ESS (Environmental Stress Screening) or even EESS (Enhanced Environmental Stress Screening). The trend has been to shorten screening time by increasing the stress level. An advanced form of burn-in has been given the descriptive name HARASS (Highly Accelerated Rapid Airflow Stress Screening).

The background philosophy for the simplest version of this kind of test is to find the weak members of a lot and avoid shipping them without spoiling the good ones and spent too much time and money.

More sophisticated programs also contained a closure of the loop by identifying root causes and correcting production processes. Further optimisation of the time under stress based on the number of failures found has been used in order to save time (see ref. [11]: IEC 61163-1).

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A major drawback of this method has always been the time. (Early burn-in specifi-cations required 168 hours without argument). In connection with HALT, however, it has been possible to introduce HASS with a dramatic increase of stress levels and thus reduction of stress exposure time to minutes.

The HASS philosophy implies:

1) Choose an efficient detection screen and fault detection system. It is catastrophic if weaknesses turned into failures by the stress exposure remain undetected. – The customer will find them. Detection screens and the coverage of fault detection systems are extremely important (see ref. [16] chapters 3.1.1 and 8).

2) Select stress levels reasonably below the levels used at HALT. Just how close seems to be a matter of experience. Ref. [17] page 44 recommends the use of seeded samples to prove that the stress is sufficient, however, ref. [16] chapter 3.13 advises against the use of seeded samples.

3) Run a test to demonstrate the safety of the chosen HASS profile. This is done by running HASS on the same specimen for a number of times. Ref. [16] says 20. Ref. [17] says minimum 10 but recommends 30 to 50. It is important that this is done on all positions of the HASS fixture because levels will vary in different places.

4) Optimise the HASS cycle by checking that it is able to find weaknesses in one pass by running 3 to 5 cycles on each production item for a certain period. If the first cycle does not catch the majority of the failures, then tune the levels and run (3) again. Ref. [16] contains a logic diagram on page 117 explaining the optimisation process.

5) Run your production through the HASS cycle. If the production processes through time comes within statistical control and the fallout is sufficiently low, consider switching to HASA (Highly Accelerated Stress Audit). This is simply HASS on a sample basis. Ref. [17] chapter 4 deals with the considerations.

Basically the same stress exposures are used as in HALT. The levels are just reduced. As in HALT, fairly wide tolerances on stress levels are accepted. The issue of uniformity and repeatability is approached in an empirical way. If the optimised HASS cycle (4) can find failures in first pass and still remain safe (3) then it is OK no matter how different the stress levels of different fixture positions may be.

The focus on failures rather than on exposures is also seen by the emphasis given to proper detection of the failures precipitated by the so-called precipitation screen. It is recognition of the fact that if failures remain undetected, they will be passed over directly to the customer who certainly will find them shortly after starting the use of the new product. In this way, the failures have not been removed, but just moved.

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In connection with detection of failures, the concepts “detection screen” and “discriminator” have been introduced.

A detection screen is an environmental exposure that takes into account the fact that the failures precipitated are often not stable, but of an intermittent nature. It reflects the well-known situation that we have all tried: Tapping the product with a screwdriver handle to find the failure that has just disappeared as we started measuring. A recommended detection screen consists of so-called tickling vibration in combination with slow change of temperature.

The discriminator is a set of measurements that allow you to detect abnormal behaviour and sort the defective ones from the good ones. The selection of the right discriminator is also a very important part of the successful managing of HASS.

3.6 Conventional tests

The most commonly used test standards are described in the following:

EN / IEC 60068

This standard contains fundamental information of environmental testing procedures, and severities of test. It contains five parts described below. Most of these IEC standards are also issued by CELELEC as EN-standards with the same number as the IEC. There are no technical differences and the following refers solely to the IEC, since this is the complete series.

IEC 60068-1

Ref. [1]: International standard IEC 60068: Environmental testing – Part 1: General and guidance.

This part of the standard defines general concepts used in connection with environmental test designed to assess the ability of specimens to perform under expected conditions of transportation, storage and all aspects of operational use. It also prescribes various atmospheric conditions for measurements, tests and for reference use.

IEC 60068-2

Ref. [2]: International standard IEC 60068: Environmental testing – Part 2: Tests.

This part of the standard contains a great number of sub-parts from IEC 60068-2-1 to IEC 60068-2-78 providing standard test procedures to determine the suitability of components, equipment or other articles to withstand specified conditions.

Most of these tests are environmental stress tests with emphasis on characteristics possibly influenced by environmental stress of a certain high level.

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A few of the tests are stress level accelerated endurance tests with emphasis on characteristics possibly influenced during time by environmental stress at accelerated level, e.g. IEC 60068-2-66 test Cx and –67 test Cy with water vapour. Other examples are the corrosion tests for salt mist IEC 60068-2-11 test Ka and –52 test Kb, and for corrosive gases –42 test Kc for sulphur dioxide, –43 test Kd for hydrogen sulphide and –60 test Ke for mixed gas.

The standard does not deal much with the relationship between natural conditions and test conditions. The main emphasis is to specify test conditions so that their effects on the tested products are reproducible. Therefore many of the tests can be used both in connection with environmental stress tests, time accelerated endurance tests and stress level accelerated endurance tests.

IEC 60068-3

This part of the standard contains sub-parts from IEC 60068-3-1 to IEC 60068-3-7 providing the background information and guidance for the test conditions in IEC 60068-2. Some parts also deal specifically with test equipment. IEC 60068-3-5 deals with the conformation of the performance of temperature chambers and –6 with combined temperature / humidity chambers. IEC 60068-3-7 specifies how to make measurements in temperature chambers with heat dissipating load. These documents do not directly specify test conditions in the present context.

IEC 60068-4

This part of the standard contains summaries of the test conditions in IEC 60068-2 intended for specification writers. This document does not directly specify test conditions in the present context.

IEC 60068-5

This part of the standard contains a guide on drafting of test methods as those in IEC 60068-2.

IEC 60721

This standard deals with classification of environmental conditions for electrotechnical products. The purpose is to form a basis for both product specifications and for test specifications. It contains the four parts described below.

IEC 60721-1

Ref. [3]: International standard IEC 60721: Classification of environmental conditions – Part 1: Environmental conditions and their severities.

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This document lists environmental parameters and a limited number of their severities within the range of conditions met by electrotechnical products when being transported, stored, installed and used. It forms the basis for selection of severity levels but does not directly specify test conditions in the present context.

IEC 60721-2

Ref. [4]: International standard IEC 60721: Classification of environmental conditions – Part 2: Environmental conditions appearing in nature.

This document presents fundamental properties, quantities for characterisation and classifications of environmental conditions relevant for electrotechnical products. It forms the basis for selection of parameters and severity levels but does not directly specify test conditions in the present context.

IEC 60721-3

Ref. [5]: International standard IEC 60721: Classification of environmental conditions – Part 3: Classification of groups of environmental conditions and their severities.

This document establishes classes of environmental conditions and their severities, covering the extreme (short-term) conditions, which may be met by a product when being transported, installed, stored, and used. Separate groups of classes are given for different product applications (e.g. weather-protected stationary, mounted in ground vehicles, transportation). The classes also take into account the degree of restriction of the use of the product from the very restricted condition (e.g. in temperature controlled rooms) to unrestricted conditions. They form the basis for selection of parameters and severity levels but do not directly specify test conditions in the present context.

IEC 60721-4

Ref. [6]: Draft standard IEC 60721: Classification of environmental conditions – Part 4-0: Guidance for the correlation and transformation of the environmental classes of IEC 60721-3 and the environmental tests of IEC 60068-2- Introduction. (104/143/CDV).

This document gives recommendations for “- environmental tests to be chosen to demonstrate the capability of a product to function or survive satisfactorily as specified in the relevant specification when subjected to the climatic and dynamic conditions given by IEC 60721-3”. It gives guidance for selection of tests but does not directly specify test conditions in the present context.

IEC 60605

This standard deals with equipment reliability testing. It contains three parts described below.

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IEC 60605-1

Ref. [7]: International standard IEC 60605: Equipment reliability testing – part 1: General requirements.

This standard provides general principles as well as specific recommendations on procedures for equipment reliability compliance and determination testing. Reliability compliance test is referred to as an experiment used to show whether or not the reliability characteristic of an item meets its stated reliability requirements. Reliability determination test is referred to as an experiment used to determine the value of a reliability characteristic of an item. Both kinds of test can be performed as either laboratory tests or field tests.

The standard does not directly specify test conditions in the present context.

IEC 60605-2

Ref. [8]: International standard IEC 60605: Equipment reliability testing – part 2: Design of test cycles.

This document applies to the design of operating and environmental test cycles referred to in 8.1 and 8.2 of IEC 60605-1: Equipment reliability testing – part 1: General requirements. 8.1 states some general considerations for the choice of test conditions. 8.2 goes more in details concerning operating and environmental test conditions. Here it is stated that: “The operating and environmental test conditions shall, whenever possible, cover the range of operating and environmental conditions prevailing during actual field use. In general, acceleration of the test by increasing the stress levels with respect to field use should not be applied.”

The method enables the design of test conditions for endurance test with some acceleration of test time versus real use time. This acceleration can be accomplished by reproducing only that part of the use conditions imposing a considerable stress on the item and omitting the conditions of low stress.

IEC 60605-3

Ref. [9]: International standard IEC 60605: Equipment reliability testing – part 3: Preferred test conditions.

This part consists of several sub-parts, containing preferred test conditions for various types of equipment:

1) Indoor portable equipment - Low degree of simulation

2) Equipment for stationary use in weather protected locations - High degree of simulation

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3) Equipment for stationary use in partially weather protected locations - Low degree of simulation

4) Equipment for portable and non-stationary use - Low degree of simulation

5) Ground mobile equipment - Low degree of simulation

6) Outdoor transportable equipment - Low degree of simulation

All of these standards specify test conditions for endurance test that intends to simulate, in a higher or lower degree, the actual conditions for use. They have not been designed with the intention of accelerating the test time in relation to real time of use.

IEC 61000

This standard deals with electromagnetic compatibility. This compatibility has two sides: susceptibility and emission. The issue of susceptibility test is in principle a kind of environmental stress test. The stress parameter in question is just an electromagnetic field, which may influence some characteristics of the product under test. The issue of emission can be seen as an unwanted function and considered a kind of reference test. The standard contains 6 parts described below.

IEC 61000-1

This part of the standard defines general concepts in connection with the application and interpretation of fundamental definitions and terms. There are two sub-parts. They do not directly specify test conditions in the present context.

IEC 61000-2

This part of the standard deals with emission of various kind of electromagnetic disturbances. There are 10 sub-parts. They all specify reference tests independent of environmental stress.

IEC 61000-3

This part of the standard deals with emission of electromagnetic disturbances related to electrical power supply lines in low voltage, medium voltage and high voltage power systems. There are 8 sub-parts. They all specify reference tests independent of environmental stress.

IEC 61000-4

This part of the standard deals with susceptibility to various kinds of electromagnetic disturbances. There are 21 sub-parts. They all specify environmental tests with emphasis on product characteristics possibly influenced by electromagnetic stress of a certain high level.

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IEC 61000-5

This part of the standard deals with protection against various kinds of electromagnetic disturbances. There are 6 sub-parts dealing with installation and mitigation guidelines. They do not directly specify test conditions in the present context.

IEC 61000-6

This part of the standard deals with susceptibility to and emission of various kinds of electromagnetic disturbances. There are 4 sub-parts.

IEC 6100-6-1, -2, and -5 deal with immunity tests for residential, industrial and power station environments. They specify environmental tests with emphasis on product characteristics possibly influenced by electromagnetic stress of a certain high level.

IEC 6100-6-4 deals with emission of electromagnetic disturbances in an industrial environment and specifies reference tests independent of environmental stress.

IEC 61014

Ref. [10]: International standard IEC 61014: Programmes for reliability growth.

This standard specifies requirements and gives guidelines for the exposure and removal of weaknesses in hardware and software items for the purpose of reliability growth. It applies when called for in the specification or when it is known that the design is immature and is unlikely to meet the requirements of a compliance test without improvement. It deals with basic concepts, management, planning, testing, failure analysis, corrective techniques and mathematical modelling.

It contains a description of testing by stressing with a general reference to Ref. [7], [8] or [9]. The following statement, however, is also found: “-, but in order to stimulate failures as quickly as possible the most severe environment and intensive use permitted by the design specification should be employed”.

This standard can be used in connection with endurance test.

IEC 61163-1

Ref. [11]: International standard IEC 61163: Reliability stress screening – part 1: Repairable items manufactured in lots.

This document describes reliability stress screening and reliability growth programmes as both aiming at improvements in the reliability found by the user. The growth programme is referred to as a development activity and not dealt with any further. Reliability stress screening is described as having the purpose to detect and remove flaws; it is part of the production process, and should not be relied upon to reveal inadequacies in design.

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The procedure for the choice of stress conditions are:

1) List possible weaknesses likely to give early failures taking into account the design and manufacturing process of the item and the expected field conditions.

2) Group weaknesses in three groups: A) Those, which cost-effectively can be removed by design or process modifications. B) Those, which cost-effectively can be removed by some kind of inspection during production. C) Remaining weaknesses.

Only the weaknesses of group C constitute the flaws that can be removed by reliability stress screening.

3) Consider the flaws and evaluate the stresses, which are most likely to develop these flaws into failures.

4) Select among the stresses identified the most efficient conditions including their sequence and/or combinations.

5) For each stress condition, evaluate the maximum stress level, which can be used without overstressing any component in the item under consideration.

The time during which the items are to be stressed depends on the failures occurring. The standard contains a procedure to determine a failure-free period that the item must show before being accepted.

This standard considers stress accelerated endurance test.

MIL-STD-810F

Ref. [12]: US military standard MIL-STD-810F: Environmental engineering considerations and laboratory tests.

The primary emphasis is: To tailor the item’s environmental design and test limits to the conditions that the specific material will experience throughout its service life, and establishing laboratory test methods that replicate the effects of environments on material rather than trying to reproduce the environments themselves.

The “F” revision has been expanded significantly up front to explain how to implement the environmental tailoring process throughout the material acquisition cycle. It is written for three basic types of users:

• Material acquisition managers. Ensuring that material will function as required in intended operational environments.

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• Environmental engineering specialists (EES) who assist combat and material developers to tailor their designs to environmental stresses/constraints expected during the service life of the material.

• Community analysts, engineers and facility operators working with evaluation, design and test by focusing on tailored designs and tests.

The document is in two parts:

• Part one – Environmental engineering program guidelines

• Part two – Laboratory test methods

The standard deals with the relationship between natural conditions and test conditions. It also specifies test conditions so that their effects on the tested products are reproducible. They are used in connection with environmental stress tests.

MIL-STD-883E

Ref. [13]: US military standard MIL-STD-883E: Test method standard, microcircuits.

This document specifies uniform methods, controls and procedures for testing microelectronic devices. This includes monolithic, multichip, film and hybrid microcircuits, microcircuit arrays, and the elements from which the circuits and arrays are formed. In this connection, it specifies suitable conditions obtainable in the laboratory and at the device level, which give test results equivalent to the actual service conditions existing in the field, and to obtain reproducibility of the results of the tests.

The standard defines absolute maximum ratings as those not to be exceeded under any measurable or known service or conditions. It allows testing ratings to exceed these limits in determining device performance or lot quality, provided that the test has been determined to be non-destructive and precautions are taken to limit device breakdown and avoid conditions that could cause permanent degradation. These testing ratings are intended to apply to short-term, stress-accelerated storage, burn-in and life tests.

The test conditions are partly environmental tests and partly stress level accelerated endurance tests.

NORMIC D6-3

Ref. [14]: NORMIC D6-3: Environmental classification of microsystems and introduction to qualification testing.

This document contains:

• A general introduction and guidance to testing.

• A grouping of microsystems based on product types and application areas.

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• An environmental classification corresponding to the grouping.

• A selection of tests applicable to the environmental classes defined.

Compared to the other test standards described in section 2.2 of the standard mentioned this document brings in no new material. The environmental classification is based on IEC 60721-3 and the selection of tests is based on IEC 60068-2. It is mainly intended for environmental tests.

JESD22

Ref. [15]: JESD22 series. This is one of several series of documents issued by the JEDEC Solid State Technology Association.

The JESD22 series specifies a great number of tests of very different type for semiconductor devices.

A few of these tests are reference tests with emphasis on characteristics independent of environmental stress, for example physical dimensions (JESD22-B100-A), external visual (JESD22-B101), coplanarity for SMD (JESD22-B108).

Some of the tests are environmental tests with emphasis on characteristics possibly influenced by environmental stress of a certain high level, for example ESD (JESD22-A114-B, JESD22-A115-A and JESD22-C101-A), vibration (JESD22-B103-A), mechanical shock (JESD22-B104-B and JESD22-B110).

Most of the tests are stress level accelerated endurance tests with emphasis on characteristics possibly influenced during time by environmental stress at accelerated level. The stress level accelerated endurance tests are especially used for the climatic environmental influence parameters, for example high temperature (JESD22-A103-B and JESD22-A108-B), change of temperature (JESD22-A100-B, JESD22-A104-B, JESD22-A105-B, JESD22-A106-A, JESD22-A113-B and JESD22-B106-B), high temperature in combination with high humidity (JESD22-A101-B, JESD22-A102-C, A110-B, JESD22-A118, and JESD22-A120).

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3.7 Test matrix - overview

TABLE 3.1 Test matrix

Test conditions Test specimen

Development samples or prototypes

Pilot production items

All of production items

Production items according to sample plan

Reference test IEC 60068-1 IEC 61000-2 IEC 61000-3 IEC 61000-6-4

IEC 60068-1 IEC 61000-2 IEC 61000-3 IEC 61000-6-4 JESD22

IEC 60068-1 JESD22

IEC 60068-1 JESD22

Environmental test IEC 60068-2 IEC 61000-4 IEC 61000-6-1 IEC 61000-6-2 IEC 61000-6-5 MIL-STD-810FNORMIC D6-3

IEC 60068-2 IEC 61000-4 IEC 61000-6-1 IEC 61000-6-2 IEC 61000-6-5 MIL-STD-810F MIL-STD-883E NORMIC D6-3 JESD22

IEC 60068-2 MIL-STD-883E JESD22

Non-accelerated endurance test

IEC 60605-2 IEC 60605-3 IEC 61014

Time-accelerated endurance test

IEC 60068-2 IEC 60605-2 IEC 61014

IEC 60068-2 IEC 60605-2 IEC 61014

Stress level accelerated endurance test

IEC 60068-2 IEC 61014 HALT

IEC 60068-2 IEC 61014 IEC 61163-1 MIL-STD-883E JESD22 HALT HASS

IEC 60068-2 IEC 61163-1 HASS

IEC 60068-2 MIL-STD-883E JESD22 HASA

3.8 Comparison of conventional and new tests

From the test matrix in section 3.7, it appears which conventional test may be comparable to the new tests. Not all tests within the same box are comparable. It is not sufficient that test conditions and test specimen are the same. Also the purpose of the test must be the same. This does not appear, since the matrix has been made only 2-dimen-sional. The possible comparisons are discussed below.

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3.8.1 Conventional vs. HALT

Possible comparisons are:

• IEC 60068-2: Reproducible environmental tests for general use.

• IEC 61014: No specific test, but a scheme for improving product quality.

• MIL-STD-883E: Environmental tests and stress level accelerated endurance tests for discriminating product quality.

• JESD22: Reference tests, environmental tests and stress level accelerated endurance tests for discriminating product quality.

As HALT mainly can be characterised as a stress level endurance test for improving product quality, it is seen that none of the conventional tests are directly comparable. Only IEC 61014 for reliability growth test has a similar approach. Since this does not deal with stress levels, the HALT must be considered as a fundamental change in test philosophy.

Therefore, even though the philosophy behind HALT is quite logical, it takes information to change the minds of involved test personnel. In the earlier days, the criterion for a successful test was no or at least few failures. As to HALT, the criterion for a successful test is now a lot of relevant failures that is possible to remove.

In conventional testing, specification limits have always been considered a kind of “holy numbers” that under no circumstances were to be exceeded. Specification limits, however, do not reflect fundamental physical limits, but merely a trade-off between stress and lifetime taking some “unavoidable” imperfections of the physical realisations into account.

The equipment fails when the accumulated damage has reached a critically high level. For mechanical stress, the fatigue damage accumulated is described by Miner’s criterion (ref. [16] page 16):

D ≈ N⋅Sβ

D is a measure of the fatigue damage accumulated, N is the number of stress cycles, S is a measure of the stress level, β is a constant depending on the material (usually ranging from 8 to 12).

From this expression it is clear that a certain critical level of accumulated damage can be reached either by many cycles of low stress or by few cycles of high stress.

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It is logical that failures are the knowledge source of possible improvements. With Miner’s criterion in mind you may also be able to convince yourself logically that the high stress levels used in HALT just reducing the waiting time. Nevertheless it takes time to learn to love the failures as sources of knowledge and overstress as a time and cost saver.

3.8.2 Conventional vs. HASS

Possible comparisons are:

IEC 60068-2: Reproducible environmental tests for general use. IEC 61163-1: Stress level accelerated endurance test for improving production processes.

As HASS mainly can be characterised as a stress level accelerated endurance test for improving production processes, it is seen that it is directly comparable to IEC 61163-1. In reliability stress screening according to IEC 61163-1, specification limits were also considered as a kind of “holy numbers”. HASS allows you to go much further than anybody would dare in the conventional approach, if only you do it in a very short time.

Taking into account that the accumulation of damage is a function of both stress level and time, also the HASS philosophy is quite logical. Anyhow, it is difficult to learn not to be afraid of spoiling good hardware by overstressing the products. However, the danger is not in “taking it over the specifications”. The danger is in not being able to detect the failures. You may have an efficient precipitation screen turning all imperfections into failures without taking any significant portion of life out of the product. If you are not able to detect these failures, not only will you miss the object of HASS, but you will also make things worse. The customer will find the failures shortly after starting the use of the product and will perceive an even worse quality than if HASS had not been performed.

HASS is therefore more than the precipitation screen formed by the stress exposure. A proper detection screen and a measuring system capable of discriminating between the good and the bad ones are equally important for the efficiency and much more important in order to avoid accidents.

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4. Failure analysis – an important tool

4.1 Failure analysis – Conventional and in relation to HALT

4.1.1 Introduction

Failure analysis of the failed samples is an important component of HALT & HASS in determining whether a given failure is relevant. An appreciation of the mechanism behind the failure increases the chances of choosing the right solution. Failure analysis can also reveal failures not found by the functional screening process.

In this chapter a brief introduction to the method and purpose of conventional failure analysis is presented. Subsequently, new aspects of the failure analysis in relation to HALT & HASS are outlined.

A more detailed understanding of failure and yield analysis methods and techniques can be found in e.g. [18].

4.1.2 Classical failure analysis

First of all the purpose of any failure or yield analysis is to be able to correct the failure and prevent it from occurring again. In order to be able to do this in an efficient manner the failure analysis has to conclude on the failure mechanism and the root cause.

The typical object for analysis could be a field failure, production failure or a failed part from all kinds of prototype testing, qualification tests, etc.

In most situations the occurrence of failure will be seen as a problem that just has to be fixed in the best way e.g. without or at least with a minimum of redesign or shift of materials/components. However, the earlier a failure/weakness is identified the easier the results may be used directly to improve design, material/component selection and to optimise the production processes.

In order to give a brief introduction to the method of failure analysis the main steps of the analysis are presented. Examples of results of different kind of analysis will be included. Information on application of some of the most important failure analysis techniques is presented in annex 2.

The first step includes characterisation of the failure and the historical data based on information gained by the client. The process of asking the client the right questions can roughly be grouped into the following categories:

1) The history of the failed and possible reference devices

2) Characterisation of the failure

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It is essential to analyse the acquired answers and maybe add more questions if the gained information does not fully characterise the failure.

Furthermore, it is also important at this first step of the analysis to make a thorough registration of received failed and reference devices (lot no., serial no., manufacturer, etc).

It should be kept in mind that to decide on the failure mechanism should not be based on this initial information solely. This could lead to loss of important evidence in the subsequent analysis by directing the choice of analysis techniques and narrow ones attention towards one possible cause of failure. This initial information should only be seen as the first important piece of the puzzle.

The second step is to cover non-destructive tests and analysis.

Typically this starts with an external visual inspection by use of optical microscopes. Subsequently electrical characterisation of the failure is performed (dependent on the degree of testing performed by the client). Other non-destructive tests included here could be X-ray inspection, SAM (Scanning Acoustic Microscope), IR-microscope and for semi/hermetic devices - also leak testing.

FIG. 4.1 X-ray micrograph showing voids in solder joints of a BGA.

void

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FIG. 4.2 SAM micrograph showing disbonding at the die paddle and tape.

X-ray does not only provide information on possible failures, melted wire bondings, delaminations, etc, but also evaluation construction information can be gained. This is important information in relation to the next step of the analysis – the destructive physical analysis.

Based on the results gained from the analysis of step 1 and 2 the first plan for the next level of the analysis must be developed.

When proceeding to the third step of the analysis, which is the DPA (Destructive Physical Analysis), care should be taken not to eliminate important evidence and not to introduce new failures. The DPA is divided into 2 parts:

1) The failure site has to be located or verified (if already located by non-destructive testing).

2) Further analysis of the failure site in order to decide on the actual failure mechanism.

This third step of the analysis may be very complex and may consist of several different analyses.

Examples of relevant analysis are:

• Decapsulation and subsequent internal visual inspection

• Hot-spot analysis

• Voltage contrast analysis

• Step-by-step cross-sectioning

• Step-by-step delamination of a die

• Examination by scanning microscope

• EDX (Energy Dispersive analysis of X-ray) analysis.

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FIG. 4.3 Optical micrograph showing cracking problem of a multilayer

ceramic capacitor. FIG. 4.4 SEM micrograph showing a cracked capacitor on a semiconductor

(cross-section).

33

FIG. 4.5 Example of an EDX spectrum.

The fourth and final step of the analysis is to conclude on the failure mechanism involved, the root cause of it and recommendations for corrective actions.

4.1.3 Failure analysis in relation to HALT - what is the difference?

First of all: All found failures are seen as a positive results because it gives the possibility to improve the product design or the production process and that is the whole purpose of performing the HALT test. It should be stressed that it is recommended to perform the test as early as possible in the development process. This could be a sub-module level in order to improve design, material/component selection and/or production processes with the minimum of costs.

There is no difference in the general method used and analysis techniques chosen when analysing failures occurred during a HALT test. Except for the time spectra it is important for the failure analyst to be “on the spot” to be able to analyse failures occurred during testing before they are modified. Some types of failures are necessary to be fixed in order to be able to continue the test and to find all relevant weaknesses.

For every failure found it should be decided whether it is relevant to make corrective actions on this or is it irrelevant to the actual field service of the tested product. At first this correlates very well to the classical approach where the goal of a failure analysis is to relate the failure mechanism to the stress conditions applied so that the risk of failure in other situations can be estimated. However, in this process it is important to remember that failure, which has been accelerated by vibration in the HALT test, may

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occur in the actual field life but it will here be accelerated by another parameter. This means that the failure mechanism must be found and then the possibility of the occurrences of this mechanism and not the type and degree of applied stress must be evaluated in relation to the products real field life.

One type of failures that may be omitted is the ones that occur because some material properties change dramatically when temperature exceeds specific values. This can be permitted if the test temperature before failure is still sufficiently higher than what is suspected to be the temperature during product field life.

In literature on HALT it is generally recommended to improve the design/process based on all observed failures as far as it is economically reasonable.

Besides the actual failure analysis it is recommended to include a thorough visual inspection supplemented by DPA on identified critical parts of the product after ended HALT test. Information gained during this analysis could add valuable information to the performed failure analysis that only includes actual failures observed during the HALT test.

Due to the nature of the HALT test it is not possible to correlate the applied stress to lifetime of the product and it is therefore not always possible to decide whether observed wear or degradation should be expected due to normal wear-out e.g. of the solder joints. However, this analysis can expose weak points not pinpointed by the electrical/-functional tests performed during the HALT test and furthermore the obtained results may be used in comparison between a new design/process and an old assembly (with known lifetime and HALT test results).

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5. Case studies This chapter presents practical case studies. The purpose of the case studies was to demonstrate the application of HALT on a number of different products for very different applications. The presentation of the cases includes all the practical aspects of a HALT e.g. criteria for selection of test specimens, function test and function test set-up, selection of HALT exposures, fixation of test specimen, summary of testing and results as well as comments and conclusion.

The case studies involved HALT on different test specimens supplied by SPM-members – mainly members of the HALT ERFA group. The test specimens were selected in order to give an idea of the large variety of products on which it is relevant to perform HALT as well as fulfilling the objective of this project. The number and variety of products are under no circumstances exhaustive.

The test specimens included the following very different applications:

• A DC/DC converter for use in jet fighters supplied by Terma A/S

• A hearing aid supplied by Oticon A/S

• Electronics for a ultra sound scanner supplied by B-K medical A/S

• Parts for a radio supplied by Bang & Olufsen A/S

The test specimens were exposed to a variety of HALT sequences in order to gather information regarding:

• Relevant HALT sequences – both classical HALT i.e. including thermo-mechanical exposures and customised HALT sequences with e.g. bounce and corrosion

• Failures found during HALT in comparison with field failures.

• Comparison between HALT and other reliability advancing methods e.g. testing, and analysis.

• A procedure for planning and performing HALT for the first time.

An overview of the case studies can be found in the test plan in table 5.1.

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TABLE 5.1 Test plan.

Test specimen Supplied by Classical HALT / Customised HALT

Purpose

DC/DC converter Terma A/S Classical HALT Comparison with other quality advancing methods

Hearing aid Oticon A/S Customised HALT

Evaluation of relevant HALT exposures other than classic HALT and comparison with field failures

Electronics for ultrasound scanner

B-K Medical A/S Classical HALT Comparison with field failures

Parts for radio Bang & Olufsen Classical HALT Comparison with other quality advancing methods

The planning of the involvement of the companies supplying the case studies was as follows:

• Initial meeting between all relevant people in the company supplying the case and DELTA in order to plan the testing.

• Performance of actual testing.

• Issue of test-log.

• Modification and re-HALT when applicable.

• Issue of updated test-log.

• Final meeting between relevant people in the company supplying the case and DELTA summing up the results of the testing, drawing conclusions and discussing comments.

• Commenting on the draft report. The companies had the right of veto regarding the inclusion of material in the description of the individual cases.

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5.1 DC/DC converter supplied by Terma A/S for use in aircrafts

5.1.1 Test specimen

The first case demonstrated classic HALT on a military (MIL) product with the aim of evaluating HALT against other quality advancing methods. MIL products are special in that respect that they are normally analysed and tested very extensively combined with the fact that they are produced in small lot sizes.

Terma A/S wanted to include this particular product in the project as it represented a generic module for both MIL and other applications i.e. not entirely a MIL product. Further, it included a process which was new to Terma A/S namely the bonding of the printed circuit board onto the frame by heat conductive adhesive.

The test specimen was a DC/DC converter module which is applicable for several products at Terma A/S, including a Tactical Data Unit used in various aircrafts such as helicopters, fighter and transport aircrafts. The Tactical Data Unit is part of a self-protection system that enhances the aircraft survivability. The system reduces the pilot workload as much as possible and enables him to choose the best response to a threat, thereby achieving maximum self-protection and minimal reaction time. The DC/DC converter is shown in fig. 5.1.

FIG. 5.1 DC/DC converter.

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The DC/DC converter was approx. 100 mm by 50 mm. It was supplied via a multi connector. Further, the converter was equipped with internal temperature sensors. These were planned to be bypassed prior to the testing in order to avoid unintentional close down of the test specimens during high temperatures testing.

The converter was mounted in the chassis by means of 2 wedgelock fasteners, which also acted as heat conductors between converter and chassis.

5.1.2 Purpose of HALT

Terma A/S has experienced that their customers are beginning to require HALT. Thus, they wanted to evaluate HALT in order to decide whether to include it in the Terma A/S requirements. Further, Terma A/S wanted to evaluate a new process e.g. the bonding process. It is new to Terma A/S to bond the printed circuit board onto the frame by means of heat conductive adhesive, Dow Corning SE-4450.

The purpose of the HALT was to evaluate HALT against other quality advancing methods as well as a tool for finding failures not found otherwise.

In accordance with Terma A/S procedures the DC/DC converter has been exposed to a number of quality advancing methods i.e.:

• In-house design guidelines (Finite Element Modelling (FEM) was not performed due to the size of the module).

• Calculations of cooling of power module via adhesive to mounting flanges (see annex 3).

• MTBF-calculations.

• Qualification testing; vibration i.e. random vibration, and Gunfire vibration according to MIL-STD-810F (see annex 3).

• ESS, i.e. temperature cycling.

5.1.3 Description of HALT

The product is a newly designed product i.e. no records of possible field failures. The inspection of the product led to believe that the majority of relevant failure mechanisms would be thermo-mechanical and secondly humidity induced. Thus it was decided to perform a classic HALT with an option for humidity.

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The sequence of the HALT was as shown schematically in fig. 5.2. Humidity exposure was omitted in the cause of testing.

FIG. 5.2 The sequence of the HALT performed on the DC/DC converter.

Further, infrared thermography was performed as a supplement to HALT in order to evaluate the cooling of the printed circuit board via frame to mounting flanges as well as the temperature distribution of the DC/DC converter.

The actually recorded temperature and vibration log is shown in fig. 5.3. The complete HALT lasted 3 days as can be seen below.

Low temperature characterisation -40°C and down in steps of 10°C

High temperature characterisation +70°C and up in steps of 15°C, 10°C, 5°C

Temperature cycling LOL - HOL, 20 cycles

Vibration characterisation in steps of approx. 10 grms

Combined temperature cycling and vibration

40

E501018 C Overall temperature and vibration log

-100

-50

0

50

100

150

12-05-2003 00:00 12-05-2003 12:00 13-05-2003 00:00 13-05-2003 12:00 14-05-2003 00:00 14-05-2003 12:00 15-05-2003 00:00

Date, time

Tem

pera

ture

[°C

]

0

20

40

60

80

100

Vibr

atio

n le

vel [

Grm

s]

AIR-TEMP PVPTC PVControl

FIG. 5.3 The recorded temperature and vibration log.

Terma A/S supplied 3 modules for the testing. The first 2 modules were tested mounted in the cabinet, whereas the last module was tested clamped directly to the vibrator plane without the motherboard and the cabinet in order to eliminate possible failures originating from the motherboard. The cabinet provided a rigid fixture, to which it was simple to connect. The cabinet with the DC/DC converter weighed approx 1.5 kg. Fig. 5.4 shows the DC/DC converter when mounted in the HALT chamber.

FIG. 5.4 The DC/DC converter mounted in the HALT chamber. Mounted via its cabinet (left) and the DC/DC converter clamped to the vibration plane via a mounting plate (right).

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The function test during HALT consisted of loading by load resistors on the 4 voltage outputs of the DC/DC converter. 4 of the voltage outputs were monitored by means of multi meters whereas 2 of the voltage outputs were monitored by means of oscilloscope. See fig. 5.5 for the function test set-up.

FIG. 5.5 The function test set-up.

The complete test log can be found in annex 3. The table 5.2 below summarises the HALT.

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TABLE 5.2 Summary of HALT of DC/DC converter performed for Terma A/S.

Exposure Remark

LOTL -70°C (start-up) -76°C (operation)

Lower Operational Temperature Limit.

LDTL Not found Lower Destruct Temperature Limit

Low temperature

Weakness Start-up unstable

UOTL +125°C Upper Operational Temperature Limit.

UDTL Not found Upper Destruct Temperature Limit

High temperature

Weakness 12 V disappeared

OVL Approx. 30 grms (loose screw), 60 grms (unstable voltages)

Operational Vibration Level

VDL Approx. 60 grms Vibration Destruct Level Vibration

Weakness Further examination required

Temperature cycling (-70°C/+125°C, 4-10 min. dwell > 20 cycles)

Weakness Not found

Combined vibration and temperature 40, 50 and 60 grms, -70°C/ +125°C

Weakness V59, V53, R104 fell off. Problems regarding the 5 VDC

After a general visual inspection performed at DELTA the conclusion was that there were found weaknesses, which can be seen in table 5.3. However, it was recommended that a thorough visual inspection should be performed on all test specimens in order to uncover other potential weaknesses. Table 5.3 also includes Terma A/S' information regarding relevance, possible cause and corrective actions as informed during the final meeting.

43

TABLE 5.3 Weaknesses found during HALT.

Relevance Possible cause Action Weakness found

Yes No (e.g. reference to failure report, etc.).

Unstable start-up of 5V and 3.3V (low temperatures) X

The characteristics started to change – ripple occurred – probably due to limit of technology.

None

12V disappeared (high temperatures) X Internal temperature limit causing

shut-down, planned to be bypassed. None

Loose PCB screw (vibration) X The screw might not be tightened

from the beginning. Locktight

Voltages dropped (high levels of vibration) X

Current sense transformer failed due to hand soldering near 70 µ Cu which drained the soldering heat. The components were designed for vapour phase soldering.

Review of production procedures

V59 and V63 fell off X Successive failure caused by the above.

Review of production procedures

R104 fell off X Further examination required

Failure during combined tem-perature cycling and vibration X

Further examination required

The infrared thermography showed that the temperature distribution was OK. It also helped in identifying the cause of failure when the current sense failed. This lead the MOSFET transistor controlling the PWM to fail leaving the diodes and rectifiers ON permanently. Further, comparing the infrared thermogram taken before and after the HALT revealed elevated temperatures of 2 pins of the connector coupling. The temperature rise was caused by fretting of the connectors due to a poor test set-up.

44

FIG. 5.6 Infrared thermogram of the component side of the DC/DC converter. Normal operation.

FIG. 5.7 Infrared thermogram of the component side of the DC/DC converter. Failure mode.

45

FIG. 5.8 Infrared thermogram of the lead side of the DC/DC converter. Failure mode. High temperature seen near the diode and rectifier.

FIG. 5.9 Infrared thermogram showing the elevated temperatures of 2 pins of the connector coupling due to fretting.

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5.1.4 Comparison with other quality advancing methods and conclusion

The purpose of the HALT performed for Terma A/S was to evaluate HALT against other quality advancing methods as well as a tool for finding failures not found otherwise.

In the following HALT is compared with the other quality advancing methods utilised by Terma A/S on this or similar projects.

The in-house design guidelines ensure that in the first place the design is in accordance with good design practice. The design guidelines include formulas for calculation of maximum displacement within the frequency range for various leaded components. It should be noted that the present printed circuit board is more rigid than usual due to the frame and the gluing process replacing the normal heat sink compound. Further, it is normal practice at Terma A/S to support large components by glue. Design failures found during HALT are to be transferred into design guidelines in the future. Thus the methods support each other, rather than excluding one another.

Calculations of the cooling of the power module performed by Terma A/S (see annex 3) showed a negligible temperature rise over the flange from the frame to chassis. This was verified by the infrared thermography.

MTBF-calculations were performed according to MIL-HDCK-217, Notice 2, the use environment, 55ºC and 30,000 h inhabited fighter. Presently, the HALT does not provide any figures for the MTBF or the life time.

Terma A/S performed qualification including random vibration and gunfire vibration i.e. sine-on random according to MIL-STD-810F. The qualification testing verified the ability of the test specimen to withstand the level of testing. No failures were found during these tests though the testing was quite severe. Generally, except the odd loose screw very few weaknesses were found during vibration testing.

Further, the qualification did not give any indication of the margin. The HALT showed that the 3 test specimens were similar with design margins way beyond the qualification limits.

The ESS performed on similar products included one temperature cycle from -40ºC to +71ºC at a rate of 10ºC/min. and 45 min. of cold soak at -40ºC and 1 h dwell at +71ºC and then back to ambient. Generally, very few weaknesses were found during ESS.

Thus, Terma A/S concluded that HALT was a valuable supplement to the quality advancing methods normally performed by Terma A/S. It provided a measure of the design margins. Further, it highlighted potential failures and workmanship failures which were not found by any of the other methods.

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5.2 Adapto BTE (Behind The Ear) hearing aid supplied by Oticon A/S

5.2.1 Test specimen

This case demonstrated customised HALT on a medical product with the aim of evaluating HALT with other exposures than "classic" HALT. Medical products are special in that respect that the requirements are very severe as it has to be verified that they are safe for humans to use.

Oticon A/Swanted to include this particular product in the project as it represented a product which Oticon A/S knew very well both with respect to testing and information from the field. Oticon A/Shad experimented accelerating various tests – in particular a corrosion test i.e. the sweat test.

The test specimen was a hearing aid called Adapto BTE. The hearing aid is shown in fig. 5.10.

FIG. 5.10 Adapto BTE hearing aid.

5.2.2 Purpose of HALT

Oticon A/S was interested in HALT but found that "classic" HALT did not fit well with the relevant failure mechanisms of their product. The failure mechanisms of primary interest were corrosion and mechanical failures originating from drops.

Oticon A/S wanted to evaluate relevant customised HALT exposures - i.e. bounce and corrosion. First of all, failure mechanisms experienced from the field seemed to point towards different thing of which corrosion and mechanical failures originating from drops were of primary interest. They also wanted to see if it was possible to design an accelerated corrosion/sweat test lasting less than a week reducing the present test time significantly. Finally, they wanted to compare weakness found during HALT with field

48

failures in order to evaluate the relevance of the failures as well as to evaluate HALT as a method.

Oticon A/S had performed a number of environmental tests both as part of product development and qualification of the product e.g.:

Qualification tests • Dry heat

• Temperature shock

• Damp heat, steady state

• Sweat (both as standard Oticon in-house procedure and extended i.e. 3 times normal duration)

• Free fall

• ESD

5.2.3 Description of HALT

Based on the considerations described in section 5.1.2 it was decided to include bounce and sweat in the HALT sequence. It consisted of:

1) Vibration characterisation by bounce.

2) Preconditioning by bounce and sweat exposure.

The bounce exposure is very effective in case of light plastic encapsulated test specimens, which are typically experiencing failures related to mechanical impact from all possible angles.

This also solves the problem that this type of product is difficult to fixture securely to the HALT vibration table during exposure to very high vibration levels.

The sequence of the HALT was as shown schematically in fig. 5.11.

The duration of the sweat exposure and the temperature/humidity cycling was longer than normally seen in HALT. This is due to the nature of the failure mechanism.

49

FIG. 5.11 The sequence of the HALT performed on the Adapto BTE hearing aid.

It was decided to use an artificial sweat which is widely used within the medical industry in Denmark and is referred to as “DIN 53160 sweat”. It had the following specification:

Sweat solution: 1 litre distilled water 5 gram NaCl 5 gram Dinatriumfosfat Acetic acid (to reach the specified ph value, approx. 3 ml)

pH: 4.7

Oticon A/S supplied 10 hearing aids for the testing. The function test during HALT included the following steps:

1) Programming in technical setting

2) Current consumption mA@1.3 V

3) Electrical/mechanical test with service software tool

4) Listening with press and twist

5) Visual check.

All steps were performed initially, whereas steps 3 - 5 were performed after each of the exposures.

Fig. 5.12 shows the function test set-up.

Vibration characterisation, bounce

Pre-conditioning by bouncing

Sweat exposure 24h@40°C/50°C/60°C/70°C/80°C

96 h@40°C

Reference

HALT

50

FIG. 5.12 The function test set-up.

Fig. 5.13 shows the Adapto BTE hearing aids ready for the bounce exposure. Where the hearing aids were lying loose and lifting from the vibration table during the exposure.

FIG. 5.13 The Adapto BTE hearing aid ready for bounce exposure.

During the sweat test the test specimens were placed on a plate in an excicator with the sweat solution in the bottom. The entire set-up was placed in a room at +40°C/+50°C/+60°C/+70°C. The air inside the excicator was changed every hour (see also fig. 5.14 below). The test specimens were unpowered during the exposure. A func-tional test and a visual inspection were performed after recovery.

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FIG. 5.14 The test specimens in the excicator during the sweat exposure.

The complete test log can be found in annex 4. The table below summarises the HALT.

5.2.4 Test results

TABLE 5.4 Summary of HALT of Adapto BTE hearing aid performed for Oticon A/S.

Exposure Remark OVL 5.0 g Operational Vibration Level

VDL 12.5 g Vibration Destruct Level Vibration - bounce

Weakness Function failure and mechanical failures

OSL 40ºC, 24 hours Operational sweat/temperature level

SDL 80ºC, 24 hours Sweat/temperature destruct level Sweat/temperature

Weakness Function failure

After a visual inspection the conclusion performed by Poul Hilding Andersson, Oticon was the weaknesses shown in table 5.5. The table also includes Oticon's information regarding relevance, possible cause and corrective action.

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Relevance Possible cause Actions / Comments Observations Photos

found in fig. 5.14

Yes No

Stay in assembly shell breaks off/shells separate

1 x Overstress during bounce/bump Failure type not seen by free fall test. Observed as field failure by service department.

VC wheel falls into instrument and cannot rotate

- x Consecutive failure from broken stay Failure type not seen by free fall test. Observed as field failure by service department.

Wire for telecoil breaks off 2 x Insufficient stress relief. Failure type not seen by free fall test. Never observed as field failure. Single strand wires are generally wear at solder joints.

PCB tracks break in flex zone 3 x Lack of flexibility/insufficient stress relief Failure type seen occasionally from rough handling of instruments in service. Not seen as field failure. No corrosion seen in connection with broken track. Possibly a consecutive failure from broken telecoil wires.

Litze wire for microphone breaks 4 x Insufficient stress relief. Failure type not seen by free fall test. Never observed as field failure. Possibly a consecutive failure from broken telecoil wires.

Compensation loop on telecoil loosens

2 x Insufficient stress relief. Adhesive type too inflexible.

Failure type not seen by free fall test. Observed as field failure by service department. Also seen during development phase as critical assembly detail.

MT0 switch fails/function failure - x Failure is most likely related to thermal overstress (80°C) of the amplifier.

Failure is not considered as relevant based on field failure data for this instrument. MT0 switch is found to be mechanically ok.

Battery drawer opens and battery may fall out

- x Holding force for battery drawer too low to withstand bump forces.

Not considered as failure. Design choice wrt. user requirements.

Microphone fails - x Possibly damaged when instrument was opened for inspection.

Failure cause not determined.

TAB

LE 5.5 W

eaknesses found during HA

LT.

53

Photo 1 Photo 2

Photo 3 Photo 4

FIG. 5.14

Photos referred to in table 5.5.

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5.2.5 Failure analysis – after exposure to artificial sweat

A failure analysis was performed after the exposure to artificial sweat at various temperatures. The failure analysis consisted of external and internal optical inspection by stereo microscope with enlargement up to 40 times. The results of the visual inspection are shown in annex 4.

In general it could be concluded that no corrosion/migration were observed. Salt residues were present inside the samples.

5.2.6 Evaluation of exposures and conclusion

The purpose of the HALT performed for Oticon A/S was to evaluate customised HALT exposures - i.e. bounce and corrosion. They also wanted to see if it was possible to design an accelerated corrosion/sweat test. Further, they wanted to compare weakness found during HALT with field failures in order to evaluate the relevance of the failures as well as to evaluate HALT as a method.

The Adapto BTE hearing aids were exposed to characterisation with bounce and pre-conditioning with bounce and sweat. The testing revealed a number of mechanical failures originating from the bounce test. Investigations on the part of Oticon A/S revealed that a number of the failures found were seen in the field or during service but not in the free fall test performed as part of the qualification testing. Thus, HALT with the bounce exposure may be considered as a useful supplement to the testing already performed by Oticon A/S.

The sweat exposure with the “DIN 53160 sweat” did not lead to any significant failures other than some was considered to be related to the high temperature. Thus, the first attempt to design an accelerated corrosion test was unsuccessful. It is generally accepted to be difficult to accelerate failures related to corrosion.

However, later failure analysis of the corrosion of field returns by means of EDX was performed on field samples in order to evaluate the composition of the artificial sweat use for the sweat exposure. The failure analysis revealed aggressive chloride (NaCl and KCl) in the corrosion on the printed circuit board and the switch, whereas Na, Ka and Oxide i.e. bases were found on the other specimens.

Thus it was suggested that future testing should include the evaluation of sweat with the 2 following compositions suggested by Oticon A/S; 1 solution comprising the same ions as sweat and 1 solution with a significantly higher concentration:

Sweat solution 1: 1 litre distilled water 9 gram NaCl 9 gram Dinatriumfosfat (Na2HPO4 · 12H2O) Approx. 3 ml. 90% lactic acid (to reach the specified ph value)

pH: 5.0

55

Sweat solution 2: 1 litre distilled water 50 gram NaCl 50 gram Dinatriumfosfat (Na2HPO4 · 12H2O) 80% acetic acid (to reach the specified ph value)

pH: 5.0

Further, it was suggested to expose open samples. This exposure will be performed as part of the next HALT project "Generalisation of HALT".

5.3 Ultrasound scanner electronics from B-K Medical A/S

5.3.1 Test specimen

The test specimen demonstrated HALT on yet another medical product with the aim of evaluating HALT by comparison with field failures.

The test specimen was a cassette for the ultrasound scanner type 2102 EXL from B-K Medical A/S. An ultrasound scanner is showing differences in acoustical impedance as 2D-images. The present scanner was designed to perform non-inversive diagnosis of the soft parts of the human body for e.g. urology, gynecology, obstetric, etc. or even as part of surgery in order to “see” what was happening before, during and after operation.

B-K Medical A/S wanted to include the cassette in the project as it is the back bone of a product family. Further, it has been in the field for 2-3 years. Thus, B-K Medical A/S has extensive information from the field.

The ultrasound scanner is shown in fig. 5.16.

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FIG. 5.16 Ultrasound scanner 2120 EXL.

The cassette consists of 3 large printed circuit boards approx. 300 mm x 400 mm and a SMPS (Switch Mode Power Supply).

B-K Medical A/S also wanted to include a small embedded PC. The PC was accessory to the scanner. The purpose of the testing was to find weak points of the embedded PC. This was particularly interesting as it might be implemented on a large number of systems. However, it was a fairly new product which was only released approx. half a year prior to the testing. Thus, B-K medical A/S had very limited field experience of the PC. However, it was decided to withdraw the PC from the testing in case it became a showstopper.

5.3.2 Purpose of HALT

A successful introduction of a portable scanner following a HALT has made B-K Medical experienced and convinced HALT users. It is company policy to perform HALT on all new products.

However, B-K Medical A/S wanted to evaluate HALT as a tool by comparing the failures found during the HALT with field failures.

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5.3.3 Description of HALT

The inspection of the product together with discussion with B-K Medical regarding their qualitative impression of the field information (no thorough analysis had been performed prior to the testing) led to believe that the majority of the relevant failure mechanisms would be thermo-mechanical. Thus it was decided to perform a classic HALT.

The sequence of the HALT was as shown schematically in fig. 5.17.

FIG. 5.17 The sequence of the HALT performed on ultrasound scanner electronics.

The actually recorded temperature and vibration log is shown in fig. 5.18. The testing was performed over 2 periods with reworking in between. The complete HALT lasted 4 days as it can be seen.

Low temperature characterisation 0°C and down in steps of 10°C

High temperature characterisation +40°C and up in steps of 10°C

Temperature cycling -20°C - +80°C, 6½ cycles

Vibration characterisation in steps of 5 grms

Reworking at B-K Medical Different extra tests at DELTA

Combined temperature cycling and vibration

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E501048 B temperature and vibration log, day 1

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E501048 B temperature and vibration log, day 3

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FIG. 5.18 The recorded temperature and vibration log, day 1 to 4.

B-K Medical A/S supplied one set of electronics together with loose modules and components for the testing. Fig. 5.19 shows the cassette, the keyboard and the PC when mounted in the HALT chamber.

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FIG. 5.19 The cassette together with the embedded PC on the side and the keyboard mounted in the HALT chamber.

The function test during HALT consisted of the steps shown in table 5.5.

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TABLE 5.5 Function test.

Test Description Low voltage Off/on at 90 VAC, Scanning with 8660 on phantom High Voltage Off/on at 264 VAC, Scanning with 8660 on phantom Nom. Voltage Off/on at 230VAC +5V D 5V digital +/- 2% (4.9 – 5.1V) +3.3VD 3.3V digital +/- 5% (0.31 - 3.47V) +5V A 5V analog +/- 5% (4.75 – 5.25V) -5V A -5V analog +/- 5% (-4.75 – -5.25V) +12V A 12V analog +/- 5% (11.4 – 12.6V) -12V A -12V analog +/- 5% (-11.4 – -12.6V) +5VD ripple Ripple on 5V digital B-Mode B-Mode scanning with 8660 on phantom B-Mode MFI 5, 7 and MHz 3-D system Capture scan Triplex Doppler on phantom Triplex Doppler noise (gain) B-Mode 1 element sweep on 8660 Test osc Analog test oscillator

Fig. 5.20 overleaf shows the fairly extensive function test set-up.

62

FIG. 5.20 The function test set-up.

The complete test log can be found in annex 6. Table 5.6 overleaf summarises the HALT.

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TABLE 5.6 Summary of HALT of ultrasound scanner electronics performed for B-K Medical A/S.

Exposure Remark

LOTL -35°C (cassette) -10°C (PC)

Lower Operational Temperature Limit.

LDTL Not found Lower Destruct Temperature Limit

Low temperature

Weakness VGA image falls out

UOTL +59°C Upper Operational Temperature Limit

UDTL Not found Upper Destruct Temperature Limit

High temperature

Weakness Scanner converting unstable

OVL Approx. 35 grms (cassette) Operational Vibration Level

VDL Approx. 30 grms (SMPS) Vibration Destruct Level Vibration

Weakness SMPS fails due to loose screw in fan

Further examination required

Temperature cycling (-20°C/+85°C, 10 min. dwell 6½ cycles)

Weakness Not found

Combined vibration and temperature 30, 40 and 50 grms, -70°C/+125°C

Weakness

Doppler and 3D function unstable (It was not possible to perform detailed function test during combined vibration/-temperature)

The conclusion after a general visual inspection performed at DELTA was that the weaknesses listed in table 5.7 were found. Table 5.7 gives also a hint on the root cause and actions as stated by B-K Medical A/S.

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TABLE 5.7 Weaknesses found by HALT.

Stress level Error description Failing module

Component

-20 to -40°C 3D system stops Error disappears when stress is removed

ZN0377 -

-20°C VGA output unstable (White stripes) ZH0743 Error not found , but similar problems seen in production during cold start at 10°C

+60°C Scanner stops after ”Switching task” ZD0767 M. osc

+60°C Fan on 3D system does not start. OK when cooled again

ZN0377 -

+70°C 3.3V shorted after adjusting master osc. ZD0767 U48 (VD7046)

+70°C Keyboard error (Not initialised) ZD0767 U51

5G Keyboard error (Not initialised) ZD0767 U51

20G Doppler stopped and B-picture was not updated ZD0767 Rework at U117

50G Lines on composite video (only visual inspection)

ZD0743 Loose capacitor ?

50G Keyboard not responsive ZH0676 C10 loose and cable to keyboard loose

50G Scanner stopped SMPS Short circuit in filter board in SMPS

50G Front-end board error, No Doppler information ZE0724 Crystal defective MB0074

50G Front-end error ZE0724 (ZE0728)

4 pcs. transmitters defective

10G temp cycle Doppler board stopped ZD0758 Trouble shooting in progress

30G temp cycle Keyboard error ZD0767 U51 and reset of NVRAM

30G temp cycle +80°C

Test impossible as master oscillator stopped ZD0767 -

50G temp cycle -20°C

Language changed during test ZD0767 Battery ?

50G temp cycle Cassette unable to start ZE0728 Defective

50G temp cycle Cassette unable to start SMPS Filterboard

50G temp cycle Cassette unable to start ZH0795 F1 loose

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5.3.4 Failure analysis of Octal D-type flip-flops

During vibration it was not possible to activate the keyboard. The 2 Octal D-type flip-flops were considered to be part of the cause of that failure. The 2 flip-flops were positioned on the same board – in the centre of the board.

The failure analysis consisted of external visual inspection, electrical measurements, X-ray inspection, chemical stripping and internal visual inspection. The complete report of failure analysis can be found in annex 5.

The I/V characterisation showed results as could be expected for one of the flip-flops (S/N 00222). Whereas output 12 of the other flip-flop (S/N 00227) was observed to be degraded, see fig. 5.21 below.

FIG. 5.21 Left: Characteristic of good flip-flop output. Right: Characteristic of flip-flop output 12 of S/N 00227.

External visual and X-ray inspection showed nothing unusual on any of the flip-flops.

By internal visual inspection after decapping a severe degradation was observed on S/N 0227 at pin 12 and on part of the GND metallisation (see figs. 5.22 and 5.23). Nothing unusual was observed on S/N 00222 after decapping.

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FIG. 5.22 Optical micrograph of S/N 0227 showing survey of the die and location of the observed degradation.

FIG. 5.23 Optical micrograph of S/N 00227 showing an enlargement of the degraded area of pin 12.

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Based on the appearance of the failure site it was concluded that excessive current load had occurred on pin 12. B-K Medical A/S was recommended to evaluate whether the functional testing performed during HALT could have caused this electrical overstress or whether the root cause of the observed failure was degradation of other components in the application.

B-K Medical A/S concluded that the error was probably caused by a bad connection in the keyboard connector. This could also explain the problems experienced during vibration, where the keyboard reacted slowly on key-press and the hourglass popping up continuously. The flip-flop controls the reset of the keyboard and the load of the cable and the input filter in the keyboard circuit, switching on and off during vibration might have caused the excessive current in the output. The flip-flop has never been reported failing in the field.

5.3.5 Evaluation of exposures and conclusion

The purpose of the HALT performed for B-K Medical A/S was to evaluate HALT as a tool by comparing the failures found during the HALT with field failures.

B-K Medical A/S went through a tedious process of transforming the field data from ASCII files into lists giving an overview of field failures. When this was done a top 10 of the failures could be listed in order of occurrence:

1) Keyboard – ZH0676

2) SMPS

3) UL0018 (not tested)

4) Doppler

5) Front end – VE5274 (HV-Mux)

6) Front end – ZE0728 (X-mit module)

7) Core board – VC1506 (Master oscillator)

8) Core board – VE5279(OP-AMP for AD converter)

9) Core board - QB0041 (battery)

10) Core board – VD7046 (U48)

When the top 10 list of field failures was compared to the failures found during HALT it could be seen that all the field failures except the UL0018 - which was not tested - were found during HALT. Further, all failures found during HALT had been seen in the field one way or the other.

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In general B-K Medical A/S viewed the HALT very positively and will go on exposing new products to HALT.

5.4 Modules for BeoSound 1 and BeoSound 3000 from Bang & Olufsen A/S

5.4.1 Test specimens

The case demonstrated HALT on audio modules with the aim of finding weaknesses as well as evaluating HALT by comparison with Bang & Olufsen A/S' Accelerated Thermal Stress Test (ATST).

The test specimens were modules for audio equipment namely BeoSound 1 and BeoSound 3000.

The modules were a Switch Mode Power Supply (SMPS) for BeoSound 1 and PCB 12 i.e. Input-select for BeoSound 3000.

The BeoSound 1 and BeoSound 3000 are shown in fig. 5.24.

FIG. 5.24 BeoSound 1 and BeoSound 3000.

5.4.2 Purpose of HALT

Bang & Olufsen A/S wanted to evaluate HALT with respect to finding potential weaknesses as well as to compare it with the Bang & Olufsen ATST.

The ATST is a famous Bang & Olufsen speciality. The purpose of the ATST is to verify that solder joints will not fail due to fatigue, which caused by improper design of solder joints, physical placement and fixation of components or mismatch between coefficients of thermal expansion for different materials. It is performed on all new printed circuit boards designed by and for Bang & Olufsen A/S.

69

5.4.3 Description of HALT

It was decided to perform a classic HALT particularly aiming at thermo-mechanical failure mechanisms in order to make it comparable to the Bang & Olufsen ATST-test.

Fig. 5.25 shows the sequence of the HALT performed.

FIG. 5.25 The sequence of the HALT performed on the modules for BeoSound 1 and BeoSound 3000.

The actually recorded temperature and vibration log is shown in fig. 5.26. As it can be seen the complete HALT lasted 3 days.

Low temperature characterisation +10°C and down in steps of 10°C by approx. 2°C/min.

High temperature characterisation +40°C and up in steps of 10°C by approx. 5°C/min.

Temperature cycling -55°C - +110°C, 30 min. dwell, 10 cycles

Vibration characterisation in steps of 5 grms

Combined temperature cycling and vibration -55°C - +110°C/ 30, 40 50 grms, 1 cycle each vibration level

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E501018 A Overall logcurve

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FIG. 5.26 The recorded temperature and vibration log, day 1 to 3.

Bang & Olufsen A/S supplied 5 SMPS modules and 3 PCB 12 in order to have extra samples for by-pass of failures and modification. Fig. 5.27 shows the modules when mounted in the HALT chamber.

SMPS PCB 12

FIG. 5.27 The SMPS module for BeoSound 1 and PCB 12 for BeoSound 3000 mounted in the HALT chamber.

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The accelerometers and temperature sensors were placed as shown in fig. 5.28.

SMPS

Accelerometer at fixture near SMPS, Z-axis

Product Temperature Control sensor (PTC)

PCB 12

Accelerometer at fixture near PCB 12, Z-axis

Accelerometer on PCB 12, Z-axis

Temperature sensor - 3

FIG. 5.28 The location of accelerometers and temperature sensor.

The modules were monitored by means of a complete Bang & Olufsen A/S equipment. The function test included power off and power on.

The complete test log can be found in annex 6.

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5.4.4 Summary of HALT

Table 5.8 below summarises the HALT.

TABLE 5.8 Summary of HALT of SMPS module for BeoSound 1 and PCB 12 for BeoSound 3000 performed for Bang & Olufsen A/S.

Exposure SMPS PCB 12 Remark

LOTL -55°C -35°C Lower Operational Temperature Limit

LDTL Not found Not found Lower Destruct Temperature Limit

Low temperature

Weakness Noise during change between radio and CD

Radio "scratches"

UOTL Not found Not found Upper Operational Temperature Limit

UDTL Not found Not found Upper Destruct Temperature Limit High temperature

Weakness (Stopped at +110°C due to test cables)

(Stopped at +110°C due to test cables)

OVL 25 grms (5 components) 30 grms by L7)

Not found Operational Vibration Level

VDL Approx. 35 grms Approx. 65 grms Vibration Destruct Level

Vibration

Weakness Mounting of C1, C21, C22, C54, C55, RT1 and L7

Mounting of C97 and C107. Mounting flange on mains bar

Temperature cycling (-55°C/+110°C, 30 min.dwell 10 cycles)

Weakness

Incipient stress symptoms at solderings of heavy com-ponents (not critical yet)

Incipient stress symptoms at solderings of heavy components (not critical yet)

Combined vibration and temperature cycling 10, 20, 30, 40 and 50 grms, -55°C and +110°C

Weakness

Problems regarding CD playing at low temperatures. Mounting of C11 and U2

Mounting of C89. Mounting flange on mains bar. Antenna connector broken in one side

73

The conclusion after a general visual inspection performed at DELTA was that the weaknesses listed in table 5.9 were found. However, it was recommended that a thorough visual inspection should be performed on all test specimens in order to uncover other potential weaknesses.

TABLE 5.9 Weaknesses found by HALT.

SMPS for BeoSound 1 Relevance Possible cause Action Re-HALT

Weakness found Yes No (e.g. reference to failure report, etc.)

Yes No

Noise during change of between radio and CD X

No

RT1 fell off X

Yes

C21, C22, C54 and C55 fell off X Bonded by adhesives in

portable equipment L7 fell off X

No

C11 fell of X

No U2 broke off X

No

CD playing stopped at low temperature/vibration X

No

PCB 12 for BeoSound 3000 Relevance Possible cause Action Re-HALT

Weakness found Yes No (e.g. reference to failure report, etc.)

Yes No

Radio "scratches" at low temperature X

C97 and C107 fell off X

C89 broke off2 X

Mounting flange of the mains bar broke off1 X

Antenna connector broke off2 X

Note 1: The mains bar was used as part of the mounting of the PCB during the HALT Note 2: Caused by the mains bar breaking off.

Bang & Olufsen A/S commented that even though the failures had been seen, it was very rarely, due to the nature of the use pattern and thus not subject to corrective actions.

5.4.5 Comparison between ATST and HALT

In order to compare the ATST and the HALT extra HALT temperature cycling were performed in addition to the previously described HALT.

74

The following tests were performed on the SMPS for BeoSound 1.

• HALT temperature cycling: -55˚C/+110˚C, up to 30 cycles air to air. The solder joints were evaluated by external visual inspection after 10, 20 and 30 cycles.

• ATST temperature cycling: +5˚C/+80˚C, up to 1500 cycles, liquid to liquid. The solder joints were evaluated by external visual inspection after each 300 cycles. The Bang & Olufsen procedure for the ATST is as follows:

1) The PCB is cleaned, if necessary, before testing, so that faulty soldered joints are easy to detect.

2) The PCB is cycled between hot and cold water baths at least 2100 times at each bath in sequences of 300 cycles followed by inspection.

3) The PCB must be in each bath for at least 300 sec.

4) The temperature in the cold bath must be below +5˚C.

5) The temperature in the hot bath must be approx. +80˚C.

6) The test period is approx. 3-4 weeks.

The results of the tests can be found in table 5.10 below.

TABLE 5.10 Results of comparison between HALT and ATST.

HALT cycling ATST cycling

10 cycles 20 cycles 30 cycles 900 cycles 1200 cycles 1500 cycles

U6 + + U2 + +

R6 U2 - D1 L2

R58 L2 L7

L7 TB1 Q1

C31 RT1 T2

C21 C15

C22 J1/JST

C55 SMD resistor

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Fig. 5.29 shows examples of solderings from Bang & Olufsen guideline for ATST with the Bang & Olufsen A/S characterisation in white print on the photo.

76

77

FIG. 5.29 Examples of solderings from Bang & Olufsen's guideline for ATST.

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Figs. 5.30 – 5.33 show photos of the failures found during HALT.

FIG. 5.30 C21.

FIG. 5.31 RT1.

79

FIG. 5.32 C22.

FIG. 5.33 U2.

80

Further, cross-sectioning of selected components from the HALT were made by Bang & Olufsen A/S. For examples see figs. 5.34, 5.35 and 5.36.

FIG. 5.34 BeoSound 1 SMPS, component U2. The soldering is characterised by degraded surface with a number of stress lines.

FIG. 5.35 BeoSound 1 SMPS, component U2. The photo was taken with fluorescence filter. A crack is seen around the component lead.

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FIG. 5.36 BeoSound 1 SMPS, component C21. Degradation of the surface with little cracks is seen. A crack in the soldering near component lead has developed. It can be seen that the cracks were caused by vibration rather than tempera- ture cycling from the way the cracks run.

5.4.6 Evaluation of test and conclusion

Bang & Olufsen A/S concluded:

• Bang & Olufsen A/S found HALT interesting. They believed that HALT could be a useful supplement to extensive testing and analysis already done by Bang & Olufsen A/S. It was found particularly interesting as a means of evaluating subsuppliers.

• Some of the results were comparable, however, in general the results obtained by HALT cycling were not the same as the ones found by the ATST cycling.

• Some of the weaknesses found during HALT occur at or near the component body rather than in the soldering e.g. cracks in the housing or broken leads. However, they still provided a good indication of weaknesses in the design.

• Both ATST and HALT helped eliminating weaknesses of the design. However, one of the tests alone would not find all weaknesses. HALT performed on a new design would certainly give a lot of hints on weaknesses, as this investigation showed good correlation between most of the weaknesses of the BeoSound 1 SMPS and field failures. However, ATST should not be omitted as a lot of the early weaknesses of the SMPS had been found and corrected by this method.

• The BeoSound 3000 PCB 12 was so robust that only very few weaknesses were found. However, this is in good correlation with the fact that field failures did not seem to occur at PCB level.

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6. Survey of results

Specification limits HALT limits found Product Application

Low temp.

High temp.

Vibration LOL UOL VOL SOL

DC/DC converter

Air fighter -40ºC +85ºC 12.6 grms -70ºC +125ºC 60 grms -

Hearing aid Human body -25ºC +55ºC - - - 7.5 grms 24 h@40ºC

Ultrasound scanner electronics

Clinic/lab -10ºC +40ºC 2 g -35ºC +59ºC 35 grms

Modules for audio equipment

Indoors living room

+10ºC 40ºC 2 grms -55ºC/-35ºC

Not found

30 grms/ Not found

-

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7. Guidelines The findings of this project resulted in the formulation of guidelines for introduction of HALT & HASS, guidelines for selection of HALT exposures and guidelines for design of HASS cycle. The guidelines are presented in this chapter.

7.1 Guideline for introduction of HALT & HASS

When introducing HALT into a company it was important to realise it was a completely new philosophy and not just a new way to do what were already done. Otherwise the results would be misinterpreted. Thus, some information as well as a lot of planning were required. In order to prepare the companies participating in this project as well as other companies performing their first HALT the checklist below was made by DELTA and supplemented by the Bang & Olufsen participants in the HALT testing.

Purpose of the testing

All involved parties have to know of the philosophy of HALT & HASS prior to the testing.

The purpose of the testing has to be decided e.g. investigation of a new product, benchmarking of different versions of a new product, investigation of field failures, benchmarking or check of subsuppliers.

Planning of the testing

• Economical and human resources have to be earmarked.

• The time frame has to be planned.

Considerations of the exposure of the test specimens

• What are the test specimens?

• Can more test specimens be tested at the same time in order to save cost?

• Is it relevant to perform the testing on sub-modules due to weight, size, thermal mass or complexity of the test specimen?

• Is it relevant to introduce a reference specimen i.e. a specimen with a well known field record, a competitive product etc. together with the actual test specimen in order to evaluate the result of the testing or to give an absolute measure of the result?

• How is the test specimen used during normal life?

• What are the specification limits?

84

• What are the top-10 list of failure mechanisms of similar products?

• What exposures are relevant?

• How is the specimen to be fixed onto the HALT vibration table?

• Who is responsible for the fixture?

• Is it relevant to reduce the thermal time constant by removing or making holes in cover plates?

• Where to place temperature sensors and accelerometers; Are there points of particular interest on the test specimen?

What to bring to the test facility

• 3-5 test specimens are desirable. However, cost and availability often have to be considered.

• Spare modules, parts and components.

• “Toolbox” with components, fuses, adhesives (a hot-melt, which stays solid above 110˚C is useful e.g. RTV 133), straps etc.

• Measuring equipment.

• Extension and connecting cables to connect to the test specimen from the outside of the HALT chamber. 2-3 m of cable are required in order to operate the equipment under test without being in the way of the HALT operator. Be aware of the temperature range of test wires. It is wise to use original connectors and solder extensions on to them. Check all wires by microscope prior to the test. Different colours of the wires are recommended – a bundle and 16 connectors – all with black wires – are difficult to distinguish.

• Diagram and manuals.

• Camera.

• ESD and clear bags for broken bits.

• A good microscope if relevant.

• “Protection box” i.e. provision for decoupling mechanical impact and keeping temperature within narrow limits e.g. for sensitive circuits which have to be inside the HALT chamber.

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Necessary manning of the test

• Designers responsible for electronics, mechanical construction or other relevant disciplines.

• Observer – responsible for reporting, registration of failures, etc.

Considerations regarding the monitoring of the function of the test specimen

• Monitoring of as many functions as possible.

• Continuous monitoring.

• Remote operation of switches, etc.

• Timing of manual operation of test specimen with respect to the HALT exposures.

• The function test sequence has to be carried out within approx. 10 min.

• Determination of malfunction criteria prior to the testing.

• Check of function test sequence and set-up the company prior to testing at HALT facility.

Evaluation of the result of the HALT

• Is the result adequate? Fig. 7.1 shows a paradigm for summarising of results?

• Is further failure analysis and root cause analysis required

• Has the action list been filled in?

• Is re-HALT required?

• Is HASS required?

• Is a HASS cycle required to be designed?

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TABLE 7.1 Paradigm for summarising of results.

Weakness Relevance Possible cause Action Re-HALT Yes No (e.g. reference to failure report, etc.

7.2 Guideline for selection of HALT exposures

The HALT exposures are selected from the list below in order to expose relevant failure mechanisms. The selection is based on an evaluation of the design of the product, a review of the top-10 list of field failures of similar products already in the field if possible as well as in-house experience.

According to Hobbs (ref. [16] the exposures may be selected from this list:

• High temperature in combination with powering and possibly reverse bias which reveals diffusion processes in Silicon, oxidation of cracks and timing problems.

• Clock variation which reveals timing problems.

• Power cycling possibly in combination with temperature cycling and 6-axis vibration which reveals thermo-mechanical weaknesses, design weaknesses and accelerated electro migration.

• Temperature cycling (particularly in combination with modulated excitation) which reveals interconnection problems, poor solderings, bonding failures and timing problems.

• Power variations in combination with temperature which reveals marginal design.

• Vibration which reveals mechanical design weaknesses e.g. large components not supported sufficiently, weak cable locks and other problems related to cabling.

• Vibration in combination with temperature cycling which reveals poor solderings.

• Humidity which reveals corrosion problems.

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• Humidity in combination with high pressure which reveals poor grounding and insulation problems.

• ESD which reveals design robustness.

• Electro Magnetic Interference which reveals design margin.

When relevant failure mechanisms have been thermo-mechanical in nature a classic HALT sequence is suggested, see below:

1) High and low temperature characterisation in order to find operating and destruct limit. Power ON/OFF.

2) Temperature cycling between the low and high operating limits.

3) Vibration characterisation; 6-axis vibration.

4) Combined temperature cycling and vibration exposure.

However, experience has shown that it can be very effective to replace 6-axis vibration by bounce in case of small plastic products which are typically experiencing failures related to mechanical impact from all possible angles. This also solves the problem that this type of product is difficult to fixture securely to the HALT vibration table during exposure to the very high vibration levels.

In other cases it has been successful to expose failures related to bonding weaknesses and interconnection of sensor cables in small light plastic products by the following sequence:

1) Temperature characterisation.

2) High temperature/humidity.

3) Low temperature.

4) Drop when product still at low temperature.

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FIG. 7.2 Drop exposure performed on test specimen still at low temperature.

When it comes to corrosion related weakness the selection of the relevant corrosive exposure has been based on a failure analysis of similar products in the market in combination with evaluation of the materials forming the design.

7.3 Guideline for design of HASS cycle

HASS is a screening test aimed at finding failures originating from the production process. The purpose of HASS is:

• to expose the largest number of latent failures at the lowest possible cost in the shortest possible time in order to reduce feedback delay.

• to establish the basis of a program of failure analysis and corrective actions for all failures found during screening.

• to increase field reliability by reducing the total number of failures sent to the market.

• to reduce the total production, screening, maintenance and warranty cost.

89

• to increase customer satisfaction and thus market share.

• to increase profit due to increased volume.

All production samples are tested and shipped to customers afterwards. Thus, the specimens are stressed well below the destruction limit. However, the duration of the HASS also has to be very short in order not to increase production time significantly. This is the trade off to be made when designing the HASS cycle. The procedure is as follows:

1) The design of the HASS cycle is based on relevant failure mechanisms.

2) HALT is performed and design failures are eliminated.

3) The first suggestion based on the results of the HALT is made.

4) 3-5 HASS cycles are performed. Failures are recorded as a function of the cycle number.

5) The HASS cycle is optimised based on Miner’s criterion in order to reduce the number of cycles to 1.

6) The resulting HASS cycle is verified.

7) Safety of HASS is verified by performing 20-50 of the resulting HASS cycles on a number of test specimens and afterwards performing a full qualification test on the same test specimens in order to verify that sufficient life is remaining in the test specimen.

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8. Discussion and conclusion The purpose of this project was to give Scandinavian companies who want to explore the new exciting test philosophy of HALT &HASS an input to decision making on when and how HALT & HASS is relevant to their product by answering the following questions:

• How does HALT & HASS fit in with other test and analysis method?

• What is there to gain from HALT & HASS?

• How do HALT results compare to field failures?

• How to get started?

• Which HALT & HASS exposures are relevant?

• How to come from HALT to HASS?

It should be noted that focus of the project was on classic HALT i.e. HALT with thermo-mechanical exposures as it fitted best with the cases supplied by the various companies.

The first question has been answered by describing HALT & HASS and relating them to other test strategies. Further, a description of failure analysis in relation to HALT is given. Failure analysis form an important part of the HALT process. From this description it can be concluded that HALT & HASS is a completely new philosophy and not just a new way of doing what has already been done for a long time. In HALT focus is on finding relevant failure mechanisms as fast and efficiently as possible rather than simulation of real environmental conditions in a well-defined and reproducible manner. It also has to be concluded that HALT & HASS is a valuable supplement to the conventional tests rather than a replacement for these tests.

The main focus of the project was on the practical part demonstrating the application of HALT on the following very different products:

• DC for aircrafts from Terma A/S

• Adapto BTE hearing aid from Oticon A/S

• Electronics for ultrasound scanner from B-K Medical A/S

• Parts for radios from Bang & Olufsen A/S

From the testing it could be concluded that there was a lot to be gained from HALT i.e.:

• Large and well-know margins of strength compared to use conditions.

• A lot of relevant failures, not found by other tests or analysis methods used by the participating companies, were revealed.

• HALT is a fast and efficient way of developing reliable products as opposed to qualification tests which are aimed at verifying that minimum requirements are

91

fulfilled. Popularly, it can be said that HALT is based on the reliability experienced by the user i.e. real life reliability.

• There is generally good correlation between failures found during HALT and field failures – this is particularly the case of thermo-mechanical failures.

• HALT is a very useful tool for fast evaluation of new processes, different variants of the same product or benchmarking of sub-suppliers.

• It is important to base the selection of HALT exposures on all relevant failure mechanisms and thus also consider customised exposures i.e. bounce, humidity and corrosion. However, due to the focus on HALT with thermo-mechanical exposures in this project. These other exposures have to be investigated further.

• It is difficult to accelerate failure mechanisms related to corrosion. It has to be further investigated.

• A new HALT project namely “Generalisation of HALT” focusing on HALT with non thermo-mechanical exposures have already been planned.

Representatives from the different companies participated in the HALT with their own product. Thus, they experienced on first hand how a HALT was prepared and performed. They were present when the test specimens failed and evaluated the relevance of the failure and took part in the repair/bypassing of the failure in order to proceed with the test. The experiences and the comments of the companies are described in the report and form the basis of the formulation of guidelines of chapter 7; guidelines for introduction of HALT & HASS, guidelines for selection of HALT exposures and guidelines for design of HASS cycle.

The guidelines for introduction of HALT & HASS were first formulated as a checklist by DELTA in order to prepare the companies participating in this project as well as other companies performing their first HALT. Later it was supplemented by the Bang & Olufsen participants in the HALT testing.

The guidelines are intended to serve as a tool for present and future users of HALT.

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Annex 1

Literature references

(2 pages)

93

Literature references

1) IEC 60068-1: Environmental testing – General and guidance.

2) IEC 60068-2: Environmental testing – Tests.

3) IEC 60721-1: Classification of environmental conditions – Environmental conditions and their severities.

4) IEC 60721-2: Classification of environmental conditions – Environmental conditions appearing in nature.

5) IEC 60721-3: Classification of environmental conditions – Classification of groups of environmental conditions and their severities.

6) IEC 60721-4: Classification of environmental conditions – Guidance for the correlation and transformation of the environmental classes of IEC 60721-3 and the environmental tests of IEC 60068-2- Introduction. (104/143/CDV).

7) IEC 60605-1: Equipment reliability testing – General requirements

8) IEC 60605-2: Equipment reliability testing – Design of test cycles.

9) IEC 60605-3: Equipment reliability testing – Preferred test conditions.

10) IEC 61014: Programmes for reliability growth

11) IEC61163-1: Reliability stress screening – Repairable items manufactured in lots

12) MIL-STD-810F: Environmental engineering considerations and laboratory tests

13) MIL-STD-883E: Test method standard, microcircuits

14) NORMIC D6-3: Environmental classification of microsystems and introduction to qualification testing. ELTA project no.: P1404-1 1999-09-22

15) JESD22 standard series from JEDEC. JEDEC Solid State Technology Association is the semiconductor engineering standardisation body of the Electronic Industries Alliance. The documents are currently published on www.jedec.org on the internet.

16) Accelerated reliability engineering. HALT and HASS. Gregg K. Hobbs. Wiley & Sons Ltd, 2000.

17) HALT, HASS & HASA Explained. Accelerated Reliability Techniques. Harry W. McLean. American Society for Quality, 2000.

18) Failure and yield analysis handbook D.L. Burgess and O.D. Trapp from Technology Associates

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19) NORMIC D6-5: Guidelines for testing of microsystems Jesper Bay, Povl K. Birch, Jens Branebjerg, Viggo Brøndegaard Nielsen, Susanne Otto, Bjarke Schønwandt, DELTA

95

Annex 2

DELTA HALT facilities

(2 pages)

T H E K N O W L E D G E C E N T R E

HALT and HASSA “vaccine” against teething troubles in new products

P127 ver.010

Why HALT and HASS?

HALT (Highly Accelerated Life Testing)

and HASS (Highly Accelerated Stress

Screening) find and rectify weaknesses

in products. The result is more reli-

able products, more satisfied custom-

ers, reduced warranty service costs

and shorter time-to-market. “Our first

HALT test run on a brand new type of

product was very positive. We found

failures that might well have resulted

in increased warranty service costs if

they hadn’t been rectified”, commented

Flemming Nielsen, Hardware Engineer

at B-K Medical A/S

What is HALT and HASS?

HALT identifies design weaknesses

whereas HASS identifies weaknesses

resulting from the manufacturing pro-

cess. Both tools are highly effective.

This capability is achieved by testing at

extreme levels, well beyond the specifi-

cations. In this way, failures are detec-

ted within a few hours instead of after

weeks of traditional testing or years on

the market.

The benefits of HALT and HASS

The advantages of HALT and HASS are:

• Huge savings in warranty and servi-

cing costs

• Shorter time-to-market

• Confidence and insights when intro-

ducing new products

• Large and known strength margins

to operational stress

• Product is mature and free from

teething troubles when it goes into

production

• Reduced rework in production

• Failures practically never occur

when product in use

• Possibility of investigating field

failures

• Customer requirements satisfied.

T H E K N O W L E D G E C E N T R E

DELTA . Venlighedsvej 4 . 2970 Hørsholm . Denmark

Tel. +45 72 19 40 00 . Fax +45 72 19 40 01 . email: halt@delta.dk

Also see www.delta.dk/halt

How is HALT carried out?

Testing procedures are selected on the

basis of relevant failure mechanisms.

There is no “standard” procedure.

Testing might include:

1. Temperature characterisation; low

and high temperatures; functional

and destruction limits defined.

Power ON/OFF

2. Extremely rapid temperature cycling

between the limits identified

3. Vibration characterisation

4. Combined temperature cycling and

vibration stress testing

5. Where relevant, combined tempera-

ture and humidity stress-testing and

cold/drop stress tests.

How is HASS carried out?

HASS testing procedure is designed

on the basis of the limits identified by

HALT. A typical procedure consists of

rapidly induced temperature changes

combined with 6-axis vibration. Tests

are of short duration - ideally lasting

just a few minutes. It is critical to

ensure sufficient lifetime remaining

in the products after screening, and

that all induced failures are found.

Otherwise the customers will discover

them later!

It is the HALT and HASS fault analysis com-bined with the improvement process that results in enhanced products.

Failure analysis

Failure analysis is an important com-

ponent of HALT and HASS in determin-

ing if a given failure is relevant. An

appreciation of the mechanism behind

the failure increases the chances of

choosing the right solution. Failure

analysis can also reveal failures not

found by the functional screening pro-

cess. Analysis is performed using tools/

techniques such as:

• External and internal visual inspec-

tions

• X-ray inspection

• Electrical metering

• Mechanical and/or chemical sec-

tioning

• Scanning Electron Microscope com-

bined with EDX analysis.

Equipment

DELTA has a dedicated HALT equipment

specially intended for temperature,

extreme rapid temperature change and

vibration stress-testing.

Dimensions:

1.06 m x 1.06 m x 1.01 m (W x D x H)

0.91 m x 0.91 m (table)

Temperature:

-100°C - +200°C, ca. 60°C/min.

Vibration:

Up to 70 grms (2 - 10 kHz), 6-axis vibra-

tion.

DELTA also has testing equipment

for e.g. thermal shock in fluid baths,

bounce tests and immediate switching

between low temperature and high

temperature and high humidity.

DELTA’s equipment for inducing rapid tempera-ture changes and 6-axis vibration.

Who stands to benefit from HALT

and HASS?

Generally speaking, HALT and HASS

are ideal for high volume and low value

products or small volume and high

value products. A number of technolo-

gies and industries are already employ-

ing HALT and HASS. These include

space technology, the military, avia-

tion, telecommunication, Information

Technology, medico, automotive, sensor

devices, metering and electronic control

devices

For further information

Contact

halt@delta.dk

Susanne Otto B.Sc.E.E., B Com(Org.),

Consultant

tel. (+45) 65 41 31 52

mobile (+45) 24 23 36 60

suo@delta.dk

or

Kim A. Schmidt, B.Sc.M.E.,

Project Manager

tel. (+45) 72 19 4271

kas@delta.dk

98

Annex 3 Case study - DC/DC converter for use in jet fighters

supplied by Terma A/S - detailed test log, “Cooling of power module”, vibrations tests

performed according to MIL-STD-810F

(7 pages)

99

100

101

DELTA/KAS Oversigt over testemner

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

Eksponering Dato "A" (ser. No. 3006) "B" (ser. No. 3004) "C" (ser. No. 3007)

Kulde 12-maj x

Varme 12-maj x

Temperaturcycling ( 1cycle) 12-maj x

Vibration 12-maj x

Temperaturcycling ( 20 + 2 cycles) 12 - 13 may x

Kombineret vibration og temperatur 14-maj x

Termovision 14-maj x x

Temperaturcycling ( 5 cycles) 14-maj x, repareret og støttelimet

Kombineret vibration og temperatur 14-maj x

Kombineret vibration og temperatur 14-maj x

Bemærkninger:Denne test blev overværet af: Jørn Gaardsvig Nielsen

Henrik IbsenPreben Simonsen

Funktionstest bestod af: Belastning på de 4 spændingsudgangeOvervågning af 4 spændingsudgange vha. multimetreOvervågning af 2 spændingudgange vha. oscilloskop

Denne HALT test blev udført vha. følgende udstyr: Thermotron AST-35 HALT test system

Unit ID

CCA, Power supply

102

DELTA/KAS Kuldeeksponering

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

ResultatAktivitet Dato Tid Init. BemærkningInitial F-test 12-maj 10:00 Ter OKNed til -40°C 12-maj 10:01 KASF-test ved -40°C 12-maj 10:12 Ter OKNed til -50°C 12-maj 10:16 KASF-test ved -50°C 12-maj 10:27 Ter OKNed til -60°C 12-maj 10:31 KASF-test ved -60°C 12-maj 10:43 Ter OK En enkelt trigning på skop (evt. støjpuls)Ned til -70°C 12-maj 10:46 KAS

F-test ved -70°C 12-maj 10:56 Ter Problemer med opstart på 5 V og 3,3 V, OK efter et par sekunder

Ned til -80°C 12-maj 11:01 KAS Input strøm svinger nogetF-test ved -80°C 12-maj 11:06 Ter Alle udgangsspændinger falder noget Forsøgt med 31 V inputLidt ekstra forsøg 12-maj 11:33 Ter Fejler ved -76°CTilabge til ambient 12-maj 11:37 KAS

Lower Operational Temperature Limit LOTL -70°C (opstart), -76°C (drift)Lower Destruct Temperature Limit LDTL Ikke fundet

DELTA/KAS Varmeeksponering

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

ResultatAktivitet Dato Tid Init. BemærkningInitial F-test 12-maj 11:52 Ter OK 2 ekstra temp. Følere, T2 på kasse og T3 på printOptil +70°C 12-maj 11:58 KASF-test ved +70°C 12-maj 12:35 Ter OKOptil +85°C 12-maj 12:35 KASF-test ved +85°C 12-maj 12:39 Ter OKOptil +95°C 12-maj 12:45 KASF-test ved +95°C 12-maj 12:50 Ter OKOptil +100°C 12-maj 12:52 KASF-test ved +100°C 12-maj 12:57 Ter OKOptil +105°C 12-maj 12:57 KASF-test ved +105°C 12-maj 13:03 Ter OKOptil +110°C 12-maj 13:03 KASF-test ved +110°C 12-maj 13:09 Ter OKOptil +115°C 12-maj 13:10 KASF-test ved +115°C 12-maj 13:13 Ter OKOptil +120°C 12-maj 13:14 KASF-test ved +120°C 12-maj 13:20 Ter OKOptil +125°C 12-maj 13:21 KASF-test ved +125°C 12-maj 13:23 Ter OKOptil +130°C 12-maj 13:24 KASF-test ved +130°C 12-maj 13:28 Ter +12 V væk ellers OK OK et kort øjeblik ved power off/onNed til +125°C 12-maj 13:30 KASF-test ved +125°C 12-maj 13:32 Ter OK efter power off/on

Upper Operational Temperature Limit UOTL +130°CUpper Destruct Temperature Limit UDTL Ikke fundet

103

DELTA/KAS Temperaturcycling

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

ResultatAktivitet Dato Tid Init. BemærkningStart cycling 12-maj 13:45 KAS OK

Temperaturcycling 12-maj KAS OK 1 cykle med 15 min dwell time. Tlow = -70°C, Thigh = +125°C.

F-test ved ambient 12-maj 16:21 Ter OK Ny power supply ("B") monteret

Temperaturcycling 12-maj 16:25 KAS Et enkelt trig på skop 20 cykles med 10 min dwell time. Tlow = -70°C, Thigh = +125°C.

F-test ved ambient 13-maj 08:05 Ter OK

Temperaturcycling 13-maj 08:10 KAS OK 2 cykles med 10 min dwell time. Tlow = -70°C, Thigh = +125°C.Ny power supply ("A") monteret

Temperaturcycling 14-maj 10:51 KAS OK 1,5 cykles med 4 min dwell time. Tlow = -70°C, Thigh = +125°C. Emne A

Ændring i program

Temperaturcycling 14-maj 11:17 KAS OK 4 cykles med 4 min dwell time. Tlow = -70°C, Thigh = +125°C. Emne A

DELTA/KAS Vibrationseksponering

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

Aktivitet Dato Tid Init. Funktion BemærkningInitial F-testRandom 10 grms 12-maj 14:49 KAS OK Ca. 10 minutterRandom 20 grms 12-maj 14:59 KAS OK Ca. 10 minutterRandom 30 grms 12-maj 15:10 KAS Løs PCB skrue efter ca. 4 minutter Ca. 4 minutter

Fejlretning 12-maj 15:18 KAS Skrue genmonteret og alle 5 skruer spændt med 0,4 Nm

Ingen locktite på skruerne

Random 30 grms 12-maj 15:26 KAS OK Måleaccelerometre falder af. Ca. 10 minutterRandom 40 grms 12-maj 15:37 KAS OK Kort pause efter ca. 1 minutRandom 50 grms 12-maj 15:51 KAS Ca. 10 minutter

Random 60 grms 12-maj 16:03 KAS Spændinger først urolige, derefter faldende Stoppet efter ca. 4 minutter

Fejlsøgning 12-maj 16:20 Ter Power supply skiftetHerefter temperaturcykling

Operational Vibration Level KAS ca. 60 grmsVibration Destruct Level KAS ca. 60 grms

Eksponering udført med random vibration i 6 akser. Minimum 10 minutter ved hvert niveau. 10 grms step

104

DELTA/KAS Kombineret vibrations- og temperatureksponering

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

Aktivitet Dato Tid Init. Resultat BemærkningInitial F-test 14-maj 08:25 Ter OKKombineret vibration og temperatur cycling

14-maj 08:30 KASLidt ustabilitet ved den sidste del af lav

temp delen. Begynder at svigte efter ca. 5 minutter ved den høje temp

1 cykle med 15 min dwell time. Tlow = -70°C, Thigh = +125°C. Vibrationsniveau 40 grms.

Funktionstest 14-maj 09:08 Ter Virker ikke, heller ikke efter power off/on

Fejlsøgning 14-maj 09:44 Ter 2 stk. komponenter (V59 og V63) faldet af.

Forstærkning af "A" 14-maj 09:59 Ter V59 og V63 støttelimet med "Super Epoxy"

Hærdet 15 minutter ved 125°C

Kombineret vibration og temperatur cycling

14-maj 12:37 KAS Problemer efter få minutter ved høj temp1 cykle med 15 min dwell time. Tlow = -70°C, Thigh = +125°C. Vibrationsniveau 40 grms.

Skiftet til anden fixturKombineret vibration og temperatur cycling

14-maj 13:50 KAS1 cykle med ca. 15 min dwell time. Tlow = -70°C, Thigh = +125°C. Vibrationsniveau 40 grms. Kørt manuelt

Kombineret vibration og temperatur cycling

14-maj 14:22 KAS Begyndende problemer med 5 V1 cykle med ca. 15 min dwell time. Tlow = -70°C, Thigh = +125°C. Vibrationsniveau 50 grms. Kørt manuelt

Kombineret vibration og temperatur cycling

14-maj 14:47 KASPermanente problemer efter få minutter

ved høj tempCa. 3 minutter ved Thigh = +125°C. Vibrationsniveau 60 grms. Kørt manuelt

Fejlsøgning Fejl kan ikke umiddelbart lokaliseres (modstand R104 faldet af)Nyt emne "C"

Kombineret vibration og temperatur cycling

14-maj 15:54 KAS1 cykle med ca. 10 min dwell time. Tlow = -70°C, Thigh = +125°C. Vibrationsniveau 60 grms. Kørt manuelt

105

DELTA/KAS Resume

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

Bemærkning

LOTL -70°C (opstart) -76°C (drift)

Lower Operational Temperature Limit.

LDTL Ikke fundet Lower Destruct Temperature Limit

Svaghed Opstart usikker

UOTL +125°C Upper Operational Temperature Limit.

UDTL Ikke fundet Upper Destruct Temperature Limit

Svaghed 12 V forsvinder

OVLca. 30 grms (løs skrue),

60 grms (ustabile spændinger) Operational Vibration Level

VDL ca. 60 grms Vibration Destruct Level

Svaghed ? Skal undersøges nærmere

Temperatur cycling(-70°C/+125°C, 4 - 10 min.dwell> 20 cycles)

Svaghed Ikke fundet

Kombineret vibration og temperatur40, 50 og 60 grms, -70°C og +125°C

SvaghedV59, V53, R104 falder af.

Problemer med 5 VDC

Bemærkning: Der bør udføres en detaljeret visuel inspektion af alle emner for at afdække eventuelle andre svagheder

Eksponering

Kulde

Varme

Vibration

DELTA/KAS Konklusioner efter overordnet visuel inspektion udført på DELTA

HALT test af DC/DC converter udført for TERMA A/S

DELTA sag nr. E501018 C

Formål At finde de svage punkter for CCA, Power Supply Her er der plads til Terma's kommentarer

Mulig årsag Aktion

Fundne svagheder Ja Nej (evt. henvisning til fejlrapport etc.) Ja NejOpstart af 5 V og 3.3 V (lave temperaturer)

12 V forsinder (høje temperaturer)

Løs PCB skrue (ved vibration)

Spændinger falder (ved høje vibrationsniveauer)

V59 og V63 falder af

R104 falder af

Fejl ved kombineret temp. cykling og vibration

Relevant RE-HALT

106

Annex 4

Case study – CQ-6263 Adapto BTE hearing aid supplied by Oticon A/S - detailed test log

(8 pages)

107

CQ-6263 Adapto HALT

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26-30 31-37Reference xVibrationskarakterisering - bounce x x xSvedtest, 40°C, prækond. med bounce x x xCyklus: Varme/fugt, kulde, bounce x x xSvedtest, 24h@50°C, prækond. med bounce x x xSvedtest, 24h@60°C, prækond. med bounce x x xSvedtest, 24h@70°C, prækond. med bounce x x xSvedtest, 24h@80°C, prækond. med bounce x xSvedtest, 96h@40°C, prækond. med bounce x x x

Svedtest II, præcond. med 10.000 P1/P2 skift x x

Fejl / testemne1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Stag i montageskal knækket - x x x x x - x x x x x x x x x x x - x x

VC hjul falder ind i apparat og kan ikke dreje

- x x x - - - - - - - - - - - - - - - - -

Tråde til telespole knækker - x x x - - - x x x x x - x x x x x - - -

Lederbaner knækker i flexzone

- x x x - - - - x - - - - - - - - - - x -

Litzetråd til mikrofon knækker

- - x x - - - - - - - - - - - - - - - - -

Kompensationssløjfe på telespole løsner

- - x - x - - - - - - - - - - x - - - - -

MT0-omskifter svigter/fejlfunktion

- - - - - - - - - - - - - - - - x x - - -

Batteriskuffe åbner sig og batteri evt. falder ud

- x x x - - - x x x x x x x x x x - - - -

Mikrofon fejler - - - - - - - - - x - - - - - - - - - - -

1Vibrationskarakterisering - bounceInitial Programering A0 ok 10-07-2003 pha

Acoustical measurements 000-000-01 10-07-2003 hlcCurrent consumption mA@1,3VEl./mech. test w/OtiTest ok 10-07-2003 phaListen w/press & twist ok 10-07-2003 phaVisual check ok 10-07-2003 pha

108

2 3 4Vibrationskarakterisering - bounceInitial Programmering A0 ok ok ok 10-07-2003 pha

Acoustical measurements 000-000-02 000-000-03 000-000-04 10-07-2003 hlcCurrent consumption mA@1,3V 1,4 1,3 1,4 10-07-2003 pha

El./mech. test w/OtiTest ok ok ok 10-07-2003 phaListen w/press & twist ok ok ok 10-07-2003 phaVisual check ok ok ok 10-07-2003 pha

Exposure: Bounce Test udført med batteri i skuffe, tændt i M mode.

Testes med lytteslange monteret, "danser" ikke så tilfældigt som øvrige.

Prop på hook Prop på hook

Sinus, 2,5g, 12Hz Exposure 15 min ok ok ok 11-07-2003 KASListen w/press & twist ok ok ok 11-07-2003 KAS/phaCurrent consumption 1,4 1,3 1,4 11-07-2003 KASEl./mech. test w/OtiTest ok ok ok 11-07-2003 phaVisual check ok ok ok 11-07-2003 KAS

Sinus, 5g, 13Hz Exposure 15 min ok ok ok 11-07-2003 KASListen w/press & twist ok ok ok 11-07-2003 KAS/phaCurrent consumption 1,4 1,3 1,4 11-07-2003 KASEl./mech. test w/OtiTest ok ok ok 11-07-2003 phaVisual check ok ok ok 11-07-2003 KAS/pha

Sinus, 7,5g, 16Hz Exposure 15 min ok ok ok 11-07-2003 KASListen w/press & twist ok ok Intet/meget svagt output

i T mode11-07-2003 KAS/pha

Current consumption 1,4 1,3 1,4 11-07-2003 KASEl./mech. test w/OtiTest ok ok ok 11-07-2003 phaVisual check ok Tydeligt slid på kant af

batteriskuffe.Tydeligt slid på kant af batteriskuffe.

11-07-2003 KAS/pha

Sinus, 10g , 16Hz Exposure 15 min Apparat reset'er af og til under testen

ok ok 11-07-2003 KAS

Listen w/press & twist ok Intet/meget svagt output i T mode

Intet/meget svagt output i T mode

11-07-2003 pha

Current consumption 1,4 1,3 1,4 11-07-2003 KASEl./mech. test w/OtiTest ok ok ok 11-07-2003 phaVisual check ok + slidmærker i

batteri/skuffe+ slidmærker i batteri/skuffe

11-07-2003 pha

Sinus, 12,5g, 19Hz Exposure 15 min Batteriskuffe åbner sig - lukket igen under test

Batteriskuffe åbner sig - lukket igen under test

Batteri falder ud af apparat - sat tilbage igen under test

11-07-2003 KAS/pha

Listen w/press & twist Fejlfunktion i T mode, støj og kratten.

Intet output Intet output 11-07-2003 pha

Current consumption 1,4 0,17 0,44 11-07-2003 KAS/phaEl./mech. test w/OtiTest VC test fail no connection no connection 11-07-2003 phaVisual check VC trykket ind i

apparatet. Skaller har åbnet sig, VC klemmer.

VC trykket skæv og ind i apparatet.

VC trykket skæv og ind i apparatet.

11-07-2003 pha

Final inspection, Oticon

Visual inspection Se ovenfor Se ovenfor Se ovenfor 28-10-2003 pha

Acoustical measurements Ingen måling, HA adskilt Ingen måling, HA adskilt Ingen måling, HA adskilt 28-10-2003 phaInternal visual inspection 2 stag knækket af på

montageskal. Rød tråd til telespole knækket ved lodning på PCB.Ledebane knækket i flexzone.

3 stag fra montageskal knækket af.Grøn tråd til telespole knækket ved spole.Rød tråd til telespole knækket ved PCB.Mik.+ litze knækket af på PCB ved lodning.Mulig kortslutning af mik. blå litze (signal) til telespole grøn PCB lodning. Telespole komp.

2 stag fra montageskal knækket af.Grøn tråd til telespole knækket ved spole.Rød tråd til telespole knækket ved PCB.Mik.+ litze knækket af på PCB ved lodning.Isolering i flexzone knækket, lederbaner afbrudt.

28-10-2003 pha

109

5 6 7Svedtest, prækond. med bounceInitial Acoustical measurements - - -

Current consumption 1,3 1,4 1,2 11-07-2003 KASEl./mech. test w/OtiTest + A0 ok ok ok 11-07-2003 phaListen w/press & twist ok ok ok 11-07-2003 phaVisual check ok ok ok 11-07-2003 pha

Præconditionering med bounce Med batteri i skuffe, men slukket apparatSinus, 7,5g, 16Hz Exposure 15 min ok ok ok 11-07-2003 KAS

Listen w/press & twist ok ok ok 11-07-2003 phaCurrent consumption 1,3 1,4 1,2 11-07-2003 KASEl./mech. test w/OtiTest ok ok ok 11-07-2003 phaVisual check slidmærker ved

batteriskuffeslidmærker ved batteriskuffe

slidmærker ved batteriskuffe

11-07-2003 KAS/pha

Svedtest 40°C 24 timer Uden batteri i skuffeListen w/press & twist ok ok ok 11-08-2003 OTCurrent consumption 1,22 1,31 1,14 11-08-2003 OTEl./mech. test w/OtiTest ok ok ok 11-08-2003 OTVisual check ? ? ? 11-08-2003 OT

Final inspection, Oticon

Visual inspection Returneret til Oticon adskilt. MTO switch klippet af og adskilt.

Returneret til Oticon adskilt.

ok 28-10-2003 pha

Acoustical measurements Ingen måling, HA adskilt ok ok 28-10-200329-10-2003

phahlc

Internal visual inspection Stag knækket. Kompensationssløjfe løs.

Probemærker på lodninger omkring MTO-switch. Bat. plus-fjeder bukket. Stag knækket.

ok 28-10-2003 pha

8 9 10Cyklus: Bounce -> varme/fugt -> kuldeInitial Acoustical measurements - - -

Current consumption 1,3 1,2 1,4 11-07-2003 KASEl./mech. test w/OtiTest + A0 ok ok ok 11-07-2003 phaListen w/press & twist ok ok ok 11-07-2003 phaVisual check ok ok ok 11-07-2003 pha

Præconditionering med bounce Med batteri i skuffe, men slukket apparatSinus, 7,5g, 16Hz Exposure 15 min ok ok Batteri faldet ud 11-07-2003 KAS

Listen w/press & twist Intet output i T mode ok ok 11-07-2003 phaCurrent consumption 1,3 1,2 1,3 11-07-2003 KASEl./mech. test w/OtiTest ok VC test fail ok 11-07-2003 phaVisual check slidmærker ved

batteriskuffeVC trykket, kan ikke roteres. slidmærker ved batteriskuffe

slidmærker ved batteriskuffe

11-07-2003 pha

Listen w/press & twist Intet output i T mode ok ok 07-07-2003 pha/kp/otCurrent consumption 1,2 1,15 1,22 07-07-2003 pha/kp/otEl./mech. test w/OtiTest ok 07-07-2003 pha/kp/otVisual check slidmærker ved

batteriskuffe07-07-2003 pha/kp/ot

11-08-2003 OTListen w/press & twist Intet output i T mode ok ok 11-08-2003 OTCurrent consumption 1,18 1,16 1,24 11-08-2003 OTEl./mech. test w/OtiTest ok ok ok 11-08-2003 OTVisual check

Vame/fugt, kulde ? ? ?

110

11 12 13Svedtest, prækond. med bounce dato initInitial Acoustical measurements - - -

Current consumption 1,20 1,17 1,25 08-08-2003 KPEl./mech. test w/OtiTest + A0 ok ok ok 07-08-2003 KP/OTListen w/press & twist ok ok ok 07-08-2003 KP/OTVisual check ok ok ok 07-08-2003 KP/OT

Præconditionering med bounce Med batteri i skuffe, men slukket apparatSinus, 7,5g, 16Hz Exposure 15 min ok ok ok 08-08-2003 KP

Listen w/press & twistCurrent consumptionEl./mech. test w/OtiTestVisual check Batteri faldet ud,

switche pos. M1, slidmærker ved batteriskuffe

Batteri faldet ud, switche pos. M1, slidmærker ved batteriskuffe

Batteriskuffe åben, switch pos. M1, slidmærker ved batteriskuffe

08-08-2003 KP

After bounce Listen w/press & twist ok - ok 11-08-2003 OTCurrent consumption 1,20 0,00 1,25 11-08-2003 OTEl./mech. test w/OtiTest ok - teleslynge virker ikke

mere 11-08-2003OT

Visual check ok ok ok 11-08-2003 OT

Svedtest, 50°C Exposure 24 timerAfter sved 50 Listen w/press & twist ok Helt død ok Teleslynge defekt 12-08-2003 OT

Current consumption 1,12 0,08 1,28 13-08-2003 OTEl./mech. test w/OtiTest ok Teleslynge defekt :: ok Teleslynge defekt 12-08-2003 OTVisual check ok ok ok 12-08-2003 OT

Final inspection, Oticon

Visual inspection Returneret til Oticon adskilt.

Returneret til Oticon adskilt.

Returneret til Oticon adskilt.

28-10-2003 pha

Acoustical measurements ok Ingen måling, HA adskilt Samlet for akustisk måling. Fejler lyttetest. Meget svagt mikrofonsignal (kontrol med FB measure).

28-10-200329-10-2003

phahlc

Internal visual inspection se Delta noter Tråd(e) til telespole knækket. PCB lederbanet knækket i bukkezone - set som markfejl (service). Se også Delta noter

Tråde(e) til telespole knækket. Coating af PCB revnet i bukkezone. Stag på montageskal knækket af.

28-10-2003 pha

111

14 15 16Svedtest, prækond. med bounce dato initInitial Acoustical measurements - - -

Current consumption 1,21 1,22 1,34 08-08-2003 KPEl./mech. test w/OtiTest + A0 ok ok ok 08-08-2003 KPListen w/press & twist ok ok ok 08-08-2003 KPVisual check ok ok ok 08-08-2003 KP

Præconditionering med bounce Med batteri i skuffe, men slukket apparatSinus, 7,5g, 16Hz Exposure 15 min ok ok ok 08-08-2003 KP

Listen w/press & twistCurrent consumptionEl./mech. test w/OtiTestVisual check Batteriskuffe åben,

switch pos. M1, slidmærker ved batteriskuffe

Batteriskuffe åben, switch pos. M2, slidmærker ved batteriskuffe

Batteri faldet ud, swith pos. M1, slidmærker ved batteriskuffe

08-08-2003 KP

After Bounce Listen w/press & twist ok ok ok 11-08-2003 OTCurrent consumption 1,22 1,23 1,29 11-08-2003 OTEl./mech. test w/OtiTest Tele slynge defekt Tele slynge defekt ok 11-08-2003 OTVisual check

Svedtest, 60°C Exposure 24 timer ok ok ok 14-08-2003 PT OT

After SVED 60 Listen w/press & twist ok ok ok 14-08-2003 OTCurrent consumption 1,09 1,14 1,18 14-08-2003 OTEl./mech. test w/OtiTest ok Teleslynge Defekt ok Teleslynge Defekt ok 14-08-2003 OTVisual check ok ok ok 14-08-2003 OT

Final inspection, Oticon

Visual inspection ok Returneret til Oticon adskilt.

Returneret til Oticon adskilt.

28-10-2003 pha

Acoustical measurements ok ok ok 29-10-2003 hlcInternal visual inspection Stag på montageskal

ved VC knækket af. Rød tråd til telespole knækket ved PCB.

se Delta noter. Coat revnet i flexzone

ok 28-10-2003 pha

17 18 19Svedtest, prækond. med bounce dato initInitial Acoustical measurements - - -

Current consumption 1,24 1,20 1,14 08-08-2003 KPEl./mech. test w/OtiTest + A0 ok ok ok 08-08-2003 KPListen w/press & twist ok ok ok 08-08-2003 KPVisual check ok ok ok 08-08-2003 KP

Præconditionering med bounce Med batteri i skuffe, men slukket apparatSinus, 7,5g, 16Hz Exposure 15 min ok ok ok 08-08-2003 KP

Listen w/press & twist ok ok ok 11-08-2003 OTCurrent consumption 1,24 1,20 1,27 11-08-2003 OTEl./mech. test w/OtiTest teleslynge defekt teleslynge defekt teleslynge defekt 11-08-2003 OTVisual check Batteriskuffe lidt åben,

switch pos. M2, akustisk tilbagekobling, slidmærker ved batteriskuffe

Batteriskuffe åben, switch pos. M1, slidmærker ved batteriskuffe

Batteriskuffe åben, switch pos. M2, slidmærker ved batteriskuffe

08-08-2003 KP

Svedtest, 70°C Exposure 24 timer ok ok ok 14-08-2003 PTAfter sved 70

Listen w/press & twist ok ok ok 15-08-2003 OTCurrent consumption 1,13 1,15 1,11 15-08-2003 OTEl./mech. test w/OtiTest teleslynge defekt teleslynge defekt teleslynge defekt 15-08-2003 OTVisual check ok ok ok 15-08-2003 OT

Final inspection, Oticon

Visual inspection Returneret til Oticon adskilt.

ok Returneret til Oticon adskilt.

28-10-2003 pha

Acoustical measurements ok ok ok 29-10-2003 hlcInternal visual inspection Stag på montageskal

knækket. Se også Delta noter.

Stag på montageskal knækket. Flex-flap med komp.sløjfe gået fra i limen på telespolen.

Stag på montageskal knækket. Flex-flap med komp.sløjfe gået fra i limen på telespolen. Se også Delta noter.

28-10-2003 pha

112

20 21Svedtest, prækond. med bounce dato initInitial Acoustical measurements - - -

Current consumption 1,23 1,26 08-08-2003 KPEl./mech. test w/OtiTest + A0 ok ok 08-08-2003 KPListen w/press & twist ok ok 08-08-2003 KPVisual check ok ok 08-08-2003 KP

Præconditionering med bounce Med batteri i skuffe, men slukket apparatSinus, 7,5g, 16Hz Exposure 15 min ok ok 08-08-2003 KP

Listen w/press & twist ok ok 11-08-2003 OTCurrent consumption 1,03 0,00 11-08-2003 OTEl./mech. test w/OtiTest Er syg Teleslynge

defektEprom test fejler - Teleslynge defekt

11-08-2003 OT

Visual check Batteriskuffe åben, switch pos. M1, slidmærker ved batteriskuffe

Switch pos. M2, akustisk tilbakobling, slidmærker ved batteriskuffe

08-08-2003 KP

Svedtest, 80°C Exposure 24 timer ok ok 15-08-2003 PTAfter sved 80 Listen w/press & twist Meget svag Opsætn

unknown Var ikke sat up OT har reloaded A0Full gain

Meget svag Opsætn unknown Var ikke sat up OT har reloaded A0Full gain 15-08-2003

OT

Current consumption 1,15 1,29 Muligt periodisk fejl ?

El./mech. test w/OtiTest Switch Test Failed Programswitch failed 18-08-2003 otVisual check ok ok 18-08-2003 ot

Final inspection, Oticon

Visual inspection Returneret til Oticon adskilt.

Returneret til Oticon adskilt.

28-10-2003 pha

Acoustical measurements MTO fejl. M og T pos. byttet om!?

MTO fejl. M og T pos. byttet om!?

28-10-200329-10-2003

phahlc

Internal visual inspection Se Delta noter. Stag knækket ved VC. 28-10-2003 pha

113

22 23 24Vibrationskarakterisering - bounceInitial 10 sept 03 Programering A0 FULL Gain ok ok ok 10-09-2003 OT

Acoustical measurements ok ok okCurrent consumption mA@1,3V 1,05 1,07 1,05 10-09-2003 OTEl./mech. test w/OtiTest ok ok okListen w/press & twist ok ok okVisual check ok ok ok

Sinus, 7,5g, 16Hz 15 min

Efter danse test Programering A0 FULL Gain ok Virker ikke mere ok 10-09-2003 OTAcoustical measurements ok okCurrent consumption mA@1,3V 1,30 0,00 1,38El./mech. test w/OtiTest ok okListen w/press & twist ok okVisual check ok ok

40 grader 4 dages sved

16-09-2003 Programering A0 FULL Gain ok Virker stadig ikke mereok 16-09-2003 OTAcoustical measurements ok okCurrent consumption mA@1,3V 1,16 0,00 1,63El./mech. test w/OtiTest ok Switch test fail

Teleslynge virker ikkeListen w/press & twist ok okVisual check ok ok

Final inspection, Oticon

Visual inspection ok ok Returneret til Oticon adskilt. MTO omskifter klippet af.

28-10-2003 pha

Acoustical measurements ok Ingen måling, HA adskilt Ingen måling, HA adskilt 28-10-200329-10-2003

phahlc

Internal visual inspection ok Stag ved VC knækket. Lederbaner knækket i bukkezone.

Se Delta noter. 28-10-2003 pha

114

Results of visual inspection of samples from artificial sweat testing

Exposure temperature

Evaluated samples Results

40ºC S/N 5, 6 One sample shows cracks in the plastic cover.

No corrosion / migration are observed. Salt residues are present inside the samples.

50ºC S/N 11, 12, 13 One or both telecoil connections are broken at the coil interface. No corrosion of the wires are observed.

In one sample (S/N 12) also the flex PCB is cracked in a bend area.

No corrosion / migration are observed. Salt residues are present inside the samples.

60ºC S/N 15, 16 One telecoil connection is broken at the coil interface in S/N 15. No corrosion of the wire is observed.

In one sample (S/N 15) also the flex PCB is cracked in a bend area – but conductor elements are still intact.

No corrosion / migration are observed. Salt residues are present inside the samples.

70ºC S/N 17, 19 One or both telecoil connections are broken at the coil interface in both samples. No corrosion of the wire is observed.

Indications of condensation residues on the gold contact pins are observed.

No corrosion / migration are observed. Salt residues are present inside the samples.

80ºC S/N 20, 21 One or both telecoil connections are broken at the coil interface in both samples. In one sample one wire is broken at the PCB. No corrosion of the wire is observed.

Indications of condensation residues on the gold contact pins are observed.

In one sample (S/N 21) the isolation of one wire is damaged in a bend area.

No corrosion / migration are observed. Salt residues are present inside the samples.

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Annex 5

Case study Ultrasound scanner 2120 EXL supplied by B-K Medical A/S

detailed test log

(31 pages)

116

A5.1 Result of cold step stress test

Cassette was initially tested at 20°C with Ok result.

Test condition: 0°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,1 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 – -12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 65% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

Test condition: -10°C Test description Result Remark 5V digital +/- 2% (4.9 –5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,2 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,1 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 – -12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 66% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

Noise on video out (Composite) VGA picture ok

117

Test condition: -20°C Test description Result Remark 5V digital +/- 2% (4.9 –5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,2 -5V analogue +/- 5% (-4.75 – -5.25V) -5,1 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 – -12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Fail Doppler on phantom Ok Doppler noise (gain) 66% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok. (not 3D)Off/on at 264 VAC, Scanning with 8660 on phantom Ok. (not 3D)

VGA picture unstable (Line sync? Tear out). Video out noisy. 3D no picture (Mouse arrow can be moved, but picture partly missing). Unable to go to 3D after switching off and on again. It was decided to continue without the 3D system

Test condition: -30°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,84 3.3V Digital +/- 5% (3.14 - 3.47V) 3,32 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -5 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 – -12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok, but

picture unstable

MFI 5.5, 7 and 8 MHz Ok Capture scan Fail Doppler on phantom Ok Doppler noise (gain) 67% 1 element sweep on 8660 0k Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok. (not 3D)Off/on at 264 VAC, Scanning with 8660 on phantom Ok. (not 3D)

VGA picture very unstable (Line sync? Tear out and picture sync. unstable). Video out noisy. Unable to go to 3D

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Test condition: -40°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,92 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,06 -5V analogue +/- 5% (-4.75 – -5.25V) -5,04 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 – -12.6V) -12,5 Ripple on 5V digital 100mv pp B-Mode scanning with 8660 on phantom Unreadable MFI 5.5, 7 and 8 MHz - Capture scan Fail Doppler on phantom Doppler is

running Doppler noise (gain) Unreadable 1 element sweep on 8660 Unreadable Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok. (not 3D)Off/on at 264 VAC, Scanning with 8660 on phantom Ok. (not 3D)

VGA picture disappeared. Composite video output very noisy and unreadable. Clock is running and the scanner is able to change mode (B-mode/ Triplex). Unable to go to 3D As the picture was unreadable it was decided to increase the temperature to 20°C again

At -20°C and much less at other temperatures. Doppler is less sensitive during temperature changes.

At -20 °C VGA picture tear out (line sync). Still unable to go to 3D, at -10°C VGA Ok, still unable to go to 3D. At 20°C 3D was okay again, everything else also OK.

3D system has a problem when starting at low temperature (<= -20°C). Ripple on 5V digital is approx. 50mV (approx. 3µs time period).

The Lower Operating Limit (LOL) was set to -20°C, where the entire cassette excl. the 3D system, was still functioning. The Lower Destruct Limit (LDL) was not found.

119

A5.2 Result of warm step stress test

An initial test was performed at room temperature before starting the warm stress test.

Test condition: 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,06 3.3V Digital +/- 5% (3.14 - 3.47V) 3,27 5V analogue +/- 5% (4.75 – 5.25V) 5,18 -5V analogue +/- 5% (-4.75 – -5.25V) -4,94 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 – -12.6V) -12,1 Ripple on 5V digital < 50 mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 80% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

Test condition: 40°C Test description Result Remark 5V digital +/- 2% (4.9 –5.1V) 4,94 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,16 -5V analogue +/- 5% (-4.75 – -5.25V) -5,04 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 81% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

120

Test condition: 50°C Test description Result Remark 5V digital +/- 2% (4.9 –5.1V) 4,84 3.3V Digital +/- 5% (3.14 - 3.47V) 3,36 5V analogue +/- 5% (4.75 – 5.25V) 5,16 -5V analogue +/- 5% (-4.75 – -5.25V) -5,04 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 81% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

Test condition: 60°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,82 3.3V Digital +/- 5% (3.14 - 3.47V) 3,36 5V analogue +/- 5% (4.75 – 5.25V) 5 -5V analogue +/- 5% (-4.75 – -5.25V) -4,96 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom - MFI 5.5, 7 and 8 MHz - Capture scan - Doppler on phantom - Doppler noise (gain) - 1 element sweep on 8660 - Analogue test oscillator - Off/on at 90 VAC, Scanning with 8660 on phantom - Off/on at 264 VAC, Scanning with 8660 on phantom -

At 59°C. The scanner picture disappeared. Video test picture Ok (Video board Ok) 3D system worked. Stopped after 'switching task'

It was decided to lower the temperature to 50°C again. At 55°C, the picture came back. Scan converting was not correct. 3D system worked but Freeze button did not work. At 50°C everything Ok again. It was decided to raise the temperature 1°C/min to investigate further.

55°C scan convertering Ok. Communication sometimes failing (freeze not always understood). 58°C.

Scan convertering Ok. Communication sometimes failing (freeze not always understood). 59°C scan converting fails.

It was decided to raise the temperature to 70°C to see if other errors appeared.

121

Test condition: 70°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,92 3.3V Digital +/- 5% (3.14 - 3.47V) 3,2 5V analogue +/- 5% (4.75 – 5.25V) 5 -5V analogue +/- 5% (-4.75 – -5.25V) -4,88 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital - B-Mode scanning with 8660 on phantom - MFI 5.5, 7 and 8 MHz - Capture scan Ok Doppler on phantom - Doppler noise (gain) - 1 element sweep on 8660 - Analogue test oscillator - Off/on at 90 VAC, Scanning with 8660 on phantom - Off/on at 264 VAC, Scanning with 8660 on phantom -

Coreboard starts, but stops after 'switching task'.

Master oscillator (120MHz) under suspicion. A local air cooling was placed in that area and it was decided to repeat the 60°C step.

Test condition: 60°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,92 3.3V Digital +/- 5% (3.14 - 3.47V) 3,55 5V analogue +/- 5% (4.75 – 5.25V) 5,16 -5V analogue +/- 5% (-4.75 – -5.25V) -5,1 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -11,9 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 81% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

At 60,1 degree picture disappeared again, but came back when the local cooling (airflow) was started. The test was performed successfully.

The temperature was raised to 70°C, but the airflow was inadequate to cool master osc. down.

12V fan on 3D system not running! The test was stopped to try to adjust the master oscillator.

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Master osc. adjusted. Afterwards 3.3V shorted. Coreboard #2001 000 000 (trouble shooting)+ videoboard. Troubleshooting 10/6 showed: 3.3V Ok. U48 (AVG/Peak controller FPGA) is getting hot (running on 3.3V). Keyboard error -> U51 does not initiate keyboard.

New Coreboard ZD0767 #2001 000 010 installed with new videoboard ZH0743 2002 100 337. Test repeated at 60°C.

Everything worked except the 12V fan on 3D did not start, after switching on at 90V.

The test was then continued at 70°C.

Test condition: 70°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,98 3.3V Digital +/- 5% (3.14 - 3.47V) 3,48 5V analogue +/- 5% (4.75 – 5.25V) 5,26 -5V analogue +/- 5% (-4.75 – -5.25V) -4,92 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Doppler on phantom Ok Doppler noise (gain) 82% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

12V fan on PC backend started during start at 25°C. Stopped at 70 °C.

Test condition: 80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,28 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom ok MFI 5.5, 7 and 8 MHz ok Capture scan ok Doppler on phantom ok Doppler noise (gain) 85% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom ok Off/on at 264 VAC, Scanning with 8660 on phantom ok

1/5-2003. Air in Doppler phantom. Flow set to 3l/h Tested before start. 12V fan Ok again!

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Test condition: 90°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,27 5V analogue +/- 5% (4.75 – 5.25V) 5,14 -5V analogue +/- 5% (-4.75 – -5.25V) -4,9 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom ok MFI 5.5, 7 and 8 MHz ok Capture scan ok Doppler on phantom ok Doppler noise (gain) - 1 element sweep on 8660 - Analogue test oscillator Off/on at 90 VAC, Scanning with 8660 on phantom Off/on at 264 VAC, Scanning with 8660 on phantom

Doppler flow changed to 6l/h. Composite out unstable. After 8 min. the screen got black (power disappeared). Temperature was lowered. Started normal again when temperature was 25°C.

A complete test was done at 20°C.

Test condition: 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,06 3.3V Digital +/- 5% (3.14 - 3.47V) 3,27 5V analogue +/- 5% (4.75 – 5.25V) 5,18 -5V analogue +/- 5% (-4.75 – -5.25V) -4,94 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,1 Ripple on 5V digital < 50 mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 80% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

It was decided to stop the high temperature test at this temperature. The Upper Operating Limit (UOL) was set to 80°C. The Upper Destruct Limit (UDL) was not found.

124

A5.3 Result of temperature cycling step stress test

The temperature cycling test was set in the interval from –20°C to +80°C. At each end temperature there was a dwell time of 10 min. where the test could be performed.

Test condition: -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,32 5V analogue +/- 5% (4.75 – 5.25V) 5,16 -5V analogue +/- 5% (-4.75 – -5.25V) -5 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 80% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested prior to the Off/On test as it was unable to start again at low temperature

Test condition: +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,02 3.3V Digital +/- 5% (3.14 - 3.47V) 3,3 5V analogue +/- 5% (4.75 – 5.25V) 5,26 -5V analogue +/- 5% (-4.75 – -5.25V) -5,08 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 85% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested after the Off/On test as it did not start again after having being stressed with the low temperature from the previous cycle. Fan on 3D system (12VDC) stopped. Backflow from air inlet! Flow on Doppler a little weaker (colours). Composite video a little unstable. Doppler ok later. Some elements are weaker during 1-element sweep (transmitters??)

125

Test condition: -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,02 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,04 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 80% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested prior to the Off/On test as it was unable to start again at low temperature

Test condition: +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,02 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -4,98 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 –-12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 85% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested after the Off/On test as it did not start again after having being stressed with the low temperature from the previous cycle.

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Test condition: -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,00 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -4,98 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 79% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested prior to the Off/On test as it was unable to start again at low temperature 1 element sweep has weak elements. Not completely reset after leaving 1 element sweep (Test osc. not turned off!!). Ok after off/on.

Test condition: +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,28 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -4,96 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Doppler on phantom Ok Doppler noise (gain) 86% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested after the Off/On test as it did not start again after having being stressed with the low temperature from the previous cycle. Some week elements in 1 element sweep

127

Test condition: -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,88 3.3V Digital +/- 5% (3.14 - 3.47V) 3,28 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -5 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital <50 mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 79% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested prior to the Off/On test as it was unable to start again at low temperature Some week elements in 1 element sweep

Test condition: +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,92 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 87% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested after the Off/On test as it did not start again after having being stressed with the low temperature from the previous cycle. Some week elements in 1 element sweep

128

Test condition: -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,88 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,02 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 80% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested prior to the Off/On test as it was unable to start again at low temperature Some week elements in 1 element sweep

Test condition: +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,88 3.3V Digital +/- 5% (3.14 - 3.47V) 3,4 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,06 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Doppler on phantom Ok Doppler noise (gain) 86% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

The 3D system was tested after the Off/On test as it did not start again after having being stressed with the low temperature from the previous cycle. Some week elements in 1 element sweep

1.5 cycles more were performed during lunch, where there are no results recorded. After the cycling the chamber was brought back to 20 degree and a final test was performed.

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Test condition: 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,88 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,06 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,5 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 80% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

130

A5.4 Result of vibration step stress test

Prior to starting the vibration the harddrive for the 3D system was removed from the system and placed in 2 strings hanging down from the ceiling of the chamber, to avoid problems with the harddrive during test.

The vibration step stress test started with 5G, but the cassette stopped working when vibration started! After removing vibration and powered up again the message ”Keyboard error” popped up on the screen. From the Coreboard ZD0767 2002 000 010 no response was received from the keyboard during initialisation. The error followed the Coreboard. (Troubleshooting 10/6-2003 showed that U51 was defective (Latch for HW programming and reset of the keyboard)). Passed the PCB test system in P4 030811/HED)

Coreboard was changed and the test continued at 5G.

Test condition: 5G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,3 5V analogue +/- 5% (4.75 – 5.25V) 5,14 -5V analogue +/- 5% (-4.75 – -5.25V) -5 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital 200mVPP B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 77% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

Doppler is less sensitive. Test osc. noise at the boarders. Video signal noisy. Ripple on power supply is steady even though power is off

131

Test condition: 10G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,9 3.3V Digital +/- 5% (3.14 - 3.47V) 3,3 5V analogue +/- 5% (4.75 – 5.25V) 5,26 -5V analogue +/- 5% (-4.75 – -5.25V) -5,08 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital 200mVPP B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Unable to

start Doppler on phantom Ok Doppler noise (gain) 66% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom OK

3D system locked up. Mouse arrow could be moved until it was turned off. Very long time starting up (Coreboard ?) showed KDB on = K 2001 and waited for approx. 30 sec. Before proceeding. This happened at both 90 and 264 V. 3D was unable to start under the test. After test the Coreboard started up at normal speed and the 3D system was working again.

Test condition: 15G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,12 3.3V Digital +/- 5% (3.14 - 3.47V) 3,26 5V analogue +/- 5% (4.75 – 5.25V) 5,26 -5V analogue +/- 5% (-4.75 – -5.25V) -5,06 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital < 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom No doppler

information Doppler noise (gain) 55%

(vibration in table)

1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok (80 sec.

start up time)

Off/on at 264 VAC, Scanning with 8660 on phantom Ok (start up time 75 sec.)

3D system on during start. OK at 10G. Switched to 2 D -> ok. Back to 3D but locked. Scanner off/on. Start-up takes a very long time. Slow reaction on a keypress. Scanner stopped during test. Off/on ->Scanner continued. (Long start-up time) and 3D got up and running again

Tape was put on trackerball on the keyboard to prevent interrupts. Start-up at 15G was faster. Scanner stopped when triplex should be tested. Off/on -> long startup time. Stopped again when selecting Triplex. Off/on -> start-up 100 sec.

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Test condition: 20G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,15 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital <50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Not runningDoppler on phantom - Doppler noise (gain) - 1 element sweep on 8660 Ok Analogue test oscillator Ok. Noisy

picture. Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

Scanner stopped 4 times when trying to run triplex.

Vibration removed. Still a problem when entering triplex mode. 3D system was running when vibration was removed.

Delayboard ZE0772 sn 000 004 changed and an extra keyboard was set externally to avoid interrupts from the trackball.

Doppler stopped with new delay board and B-picture was not updated, during ramp from 0 to 20G within 5 min. It stopped at 0.3G. It was decided to change the delay board.

ZE0772 000 001 was inserted instead. Knocking on the cassette caused the scanner to stop. An error was found on the Coreboard (rework on U117).

The original delay board was therefore tested and found ok. Original delay board ZE0772 (000 004) was inserted again and test continued. First ramping from 10G to 20G, then continuing at 20G.

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Test condition: 20G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,16 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,3 Ripple on 5V digital 150mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan . Doppler on phantom . Doppler noise (gain) approx. 60%

(noise from movement)

1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

3D does not start. The start speed was normal after keyboard disconnected and external keyboard attached.

External keyboard attached during further testing.

Test condition: 25G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -5,06 12V analogue +/- 5% (11.4 – 12.6V) 12,2 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital 150mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) approx.

55-60% 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

3D does not start.

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Test condition: 30G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -5,06 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) Approx.

55% noisy 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom OK

3D does not start. Vibration removed and system was able to start and perform a scan.

Test condition: 35G @ 20 °C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,94 3.3V Digital +/- 5% (3.14 - 3.47V) 3,28 5V analogue +/- 5% (4.75 – 5.25V) 5,2 -5V analogue +/- 5% (-4.75 – -5.25V) -5,12 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,3 Ripple on 5V digital 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok!! Doppler on phantom Ok Doppler noise (gain) ?? Noisy 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

3D is running again!

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Test condition: 40G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,2 -5V analogue +/- 5% (-4.75 – -5.25V) -5,12 12V analogue +/- 5% (11.4 – 12.6V) 12,2 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital 50mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) ?? Noisy 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

3D does not start. Picture is noisy. Some stribes in ultrasound picture (with 8660 transducer). Vibration removed and scanner turned off and on again. 3D system was running

Test condition: 45G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,96 3.3V Digital +/- 5% (3.14 - 3.47V) 3,24 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -5,06 12V analogue +/- 5% (11.4 – 12.6V) 12,2 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital 50mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok, but

noisy Doppler noise (gain) ?? Noisy 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

3D system worked at 40G, when vibration was started after 3D was up and running. Stopped after 6 min. @ 45G

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Test condition: 50G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,98 3.3V Digital +/- 5% (3.14 - 3.47V) 3,28 5V analogue +/- 5% (4.75 – 5.25V) 5,08 -5V analogue +/- 5% (-4.75 – -5.25V) -5,08 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,4 Ripple on 5V digital 50mV pp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) ?? Noisy 1 element sweep on 8660 Ok Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

3D not running. Vibration stopped and system restarted. 3D was running. Vibration started after 3D was restarted. After 8 min. 3D was still working. Lines appeared on the captured image. Went to 2D -> lines in picture. Size was changed and lines disappeared. Back to 3D still -> ok. After 13 min. the capture stopped (unresponsive). System restarted. The 2D system started, but stopped when scanning was started (possible watchdog shutdown).

After the test, Dornier logo has now changed to BK logo and date/time was not correct. A RAM checksum error must have occurred and the Coreboard must have set the contents to default value (a possible battery problem).

Composite video output was very noisy.

Vibration removed and system restarted -> ok. Vibration on again -> 40G. 2D system started up but crashed as scanning was started. Lines on composite video out. Possible bad connection on videoboard (As the videocard was a Prototype card without number it was checked and one capacitor seemed loose, but no further troubleshooting was performed).

Vibration was removed and everything was running again.

Keyboard in chamber was checked. TGC potmeters and trackball worked, but keyboard was unresponsive.

After changing the front-end board (ZE0724) sn 000 013 to sn 000 109 vibration was started again ramping from 40 to 50G. The scanner did not stop this time, but after 5 min. the scanner stopped as the power supply failed. It turned out to be a screw from one of the fans that had gone loose and short circuited the power supply filter. The filter was changed.

After the filter had been changed no doppler information could be found. Front-end board was changed (ZE0724 #000 102) to the old board #000 109.

Further troubleshooting showed that the 2 front-end boards were not working (no doppler information / Transmitter errors).

137

A5.5 Result of combined temperature cycle and vibration step stress test

The test was performed 29/9 2003 with. SW version 0.140 24-09-2003 (Improved doppler).

Initial pretest:

Test condition: 0G @ 20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,02 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,26 -5V analogue +/- 5% (-4.75 – -5.25V) -5,18 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mvPP B-Mode scanning with 8660 on phantom ok MFI 5.5, 7 and 8 MHz ok Capture scan Ok Doppler on phantom ok Doppler noise (gain) 65% 1 element sweep on 8660 - Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom

Ok

Off/on at 264 VAC, Scanning with 8660 on phantom

Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning.

During the initial temperature cycling test from -20 t0 +80 deg the cassette stopped at 61°C

The master osc. was adjusted. 1/8 Rp counter-CW. Seemed a little better as it was ok to 70°C

Adjusted 1/8 more. Ferrite defective.

Therefore a new coreboard was inserted. It was decided to continue the test even though the cassette stops.

The new coreboard was equipped with SW dated 14/5-2003.12.13

A quick test was done to determine the state of the master oscillator:

• @60°C Ok still functioning.

• @70°C Ok still functioning.

• @80°C Ok still functioning.

Back to 20°C test start at -20 to 80 deg and vibration 10G.

138

Test condition: 10G @ -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,4 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,12 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom

Ok

Off/on at 264 VAC, Scanning with 8660 on phantom

Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during tempera-ture changes with vibration

Doppler did not work when stress was removed. Doppler board ZD0758 sn 000 264 inserted instead of sn 000 104. Jumper J5 almost off. New board tested ok. Test continued.

139

Test condition: 20G @ -20°C to 80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V digital +/- 5% (3.14 - 3.47V) 3,4 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,18 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mvPP B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz OK Capture scan Can be

selected but not

operated Doppler on phantom ok Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom

1)

Off/on at 264 VAC, Scanning with 8660 on phantom

2)

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during tempera-ture changes with vibration. 1) KBD on =K 2001.

Stops here without getting further. When vib removed ok. Error is related to keyboard. Keyboard removed and test ok. TGC line visible always (Indicates that the keyboard is active)

2) At -20 deg 20G See 1) Works at -20°C without vib.

To avoid interruptions from the keyboard during the test the keyboard was removed and the test continued.

140

Test condition: 20G @ ~50°C rising

temperature Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 4,98 3.3V Digital +/- 5% (3.14 - 3.47V) 3,34 5V analogue +/- 5% (4.75 – 5.25V) 5,24 -5V analogue +/- 5% (-4.75 – -5.25V) -5,18 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom

Ok

Off/on at 264 VAC, Scanning with 8660 on phantom

Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during tempera-ture changes with vibration. 3D unable to start during stress

Keyboard is interrupting all the time (hourglass) even though only an external keyboard is attached (No keyboard in the chamber).

This might indicate a bad connection either to the supply voltage or to the reset line. Doppler gate is moving during vibration, when keyboard is connected (absolutely no movement on trackball) the gate is ok when vibration is removed.

141

Test condition: 30G @ ~-15°C falling

temperature Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,34 5V analogue +/- 5% (4.75 – 5.25V) 5,2 -5V analogue +/- 5% (-4.75 – -5.25V) -5,16 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -18 Ripple on 5V digital 25mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator OK Off/on at 90 VAC, Scanning with 8660 on phantom

Ok

Off/on at 264 VAC, Scanning with 8660 on phantom

Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during tempera-ture changes with vibration. 3D unable to start during stress

Test condition: 30G @ ~50 °C rising

temperature Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,36 5V analogue +/- 5% (4.75 – 5.25V) 5,22 -5V analogue +/- 5% (-4.75 – -5.25V) -5,16 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Doppler on phantom Ok Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom

1)

Off/on at 264 VAC, Scanning with 8660 on phantom

1)

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during temperature changes with vibration. 3D unable to start during stress 1) Unable to start. Stops after ”switching task”

Keyboard error. Unable to start. Stops after ”switching task”. Coreboard (ZD0767 sn 000 002 ) was inserted to see if the Coreboard was the problem.

142

The new coreboard was OK, but the hourglass still occurred during vibration.

U51 changed on coreboard, but the coreboard had to be reset (setting NVRAM to default) to enable power up.

143

Test condition: 30G @ -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,24 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,04 -5V analogue +/- 5% (-4.75 – -5.25V) -5,18 12V analogue +/- 5% (11.4 – 12.6V) 11,9 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mvPP B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom

Ok

Off/on at 264 VAC, Scanning with 8660 on phantom

Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during temperature changes with vibration. 3D unable to start during stress

Test condition: 30G @ +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5.04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,22 -5V analogue +/- 5% (-4.75 – -5.25V) -5,2 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mvpp B-Mode scanning with 8660 on phantom NA MFI 5.5, 7 and 8 MHz NA Capture scan NA Doppler on phantom NA Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator NA Off/on at 90 VAC, Scanning with 8660 on phantom

Ok 1)

Off/on at 264 VAC, Scanning with 8660 on phantom

Ok 1)

Test at +80°C was impossible as master osc. on the new coreboard stopped. 1) Until after switching task

As a complete functional test could not be performed because the master oscillator stopped, the temperature was set to 20 °C and the functional test performed.

144

Test condition: 30G @ +20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5.04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,18 -5V analogue +/- 5% (-4.75 – -5.25V) -5,16 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,5 Ripple on 5V digital 25mV B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok Doppler on phantom Ok Doppler noise (gain) 68% 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during temperature changes with vibration.

As the result was satisfying it was decided to continue the test at 40G.

Test condition: 40G @ -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 5,22 -5V analogue +/- 5% (-4.75 – -5.25V) -5,14 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during temperature changes with vibration. 3D unable to start during stress. Composite video out is flickering

145

Test condition: 40G @ +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,34 5V analogue +/- 5% (4.75 – 5.25V) 5,28 -5V analogue +/- 5% (-4.75 – -5.25V) -5,14 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mV B-Mode scanning with 8660 on phantom NA MFI 5.5, 7 and 8 MHz NA Capture scan NA Doppler on phantom NA Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator NA Off/on at 90 VAC, Scanning with 8660 on phantom Ok 1) Off/on at 264 VAC, Scanning with 8660 on phantom Ok 1)

Test at +80°C was impossible as master osc. on the new coreboard stopped. 1) Until after switching task

Stress was removed shortly to make a functional test

Test condition: 0G @ +20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,38 5V analogue +/- 5% (4.75 – 5.25V) 4,96 -5V analogue +/- 5% (-4.75 – -5.25V) -5,14 12V analogue +/- 5% (11.4 – 12.6V) 12,1 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan Ok 1) Doppler on phantom Ok Doppler noise (gain) 69% 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during temperature changes with vibration. 1) The 3D system did not respond the first time (Windows regenerating. But was Ok after windows had restarted.

146

The test was continued at 50G.

Test condition: 50G @ -20°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,04 3.3V Digital +/- 5% (3.14 - 3.47V) 3,4 5V analogue +/- 5% (4.75 – 5.25V) 5,22 -5V analogue +/- 5% (-4.75 – -5.25V) -5,16 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mVpp B-Mode scanning with 8660 on phantom Ok MFI 5.5, 7 and 8 MHz Ok Capture scan - Doppler on phantom Ok 1) Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator Ok Off/on at 90 VAC, Scanning with 8660 on phantom Ok Off/on at 264 VAC, Scanning with 8660 on phantom Ok

1 element sweep could not be tested as the Com port on the attached PC was not functioning. Doppler could not be tested with stress as it was too noisy during temperature changes with vibration. 3D unable to start during stress Composite video flickering. Language switched during test!! (after power down). 1) Doppler stopped. Power down and up again. Doppler ok.

Test condition: 50G @ +80°C Test description Result Remark 5V digital +/- 2% (4.9 – 5.1V) 5,06 3.3V Digital +/- 5% (3.14 - 3.47V) 3,36 5V analogue +/- 5% (4.75 – 5.25V) 5,26 -5V analogue +/- 5% (-4.75 – -5.25V) -5,14 12V analogue +/- 5% (11.4 – 12.6V) 12 -12V analogue +/- 5% (-11.4 –-12.6V) -12,6 Ripple on 5V digital 25mVpp B-Mode scanning with 8660 on phantom NA MFI 5.5, 7 and 8 MHz NA Capture scan NA Doppler on phantom NA Doppler noise (gain) NA 1 element sweep on 8660 NA Analogue test oscillator NA Off/on at 90 VAC, Scanning with 8660 on phantom Ok 1) Off/on at 264 VAC, Scanning with 8660 on phantom Ok 1)

At 60°C the master osc stopped. Only partial test performed Composite video flickering. 1) until ”switching task”

As the functional test could not be completed at +80°C the stress was remove after 10 min. to make a functional test at +20°C.

However, when the stress was removed the scanner was unable to start. The trouble shooting showed that one transmitter module (ZE0728) was defective, a fuse on the motherboard was damaged and the power supply had 2 errors.

The fan did not run (had to be changed).

Transformer on the filter board had a loose connection.

147

Annex 6

Case study Modules for BeoSound 1 and BeoSound 3000

supplied by Bang & Olufsen A/S – detailed test log

(7 pages)

148

DELTA/KAS Oversigt over testemner

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

Eksponering Dato Nr. 1 Nr. 2 Nr. 3 Nr. 4 Nr. 5 Nr. 1 Nr. 2 Nr. 3

Kulde 14-apr x x

Varme 14-apr x x

Temperaturcycling 14-apr x x

Vibration optil 15 grms 15-apr x x

Vibration optil 25 grms 15-apr x x

Vibration ved 25 grms 15-apr x (x) x x

Vibration ved 30 grms 15-apr x x

Ekstra temperaturtest 15-apr x

Vibration ved 35 grms 15-apr x

Vibration optil 65 grms 15-apr x

Kombineret vibration og temperatur 16-apr x med ny metal vinkel

Bemærkninger:

Overvågning lavet vha. komplette B&O apparater F-test inkluderer power off/on

Test overvåget af: Turi Bach RoslundMogens Agger

Unit ID

PCB 12 (Input-select til BeoSound 3000)SMPS (til BeoSound 1)

149

DELTA/KAS Kuldeeksponering

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

Aktivitet Dato Tid Init. SMPS PCB 12 BemærkningInitial F-test 14-apr 11:30 B&O OK OK

F-test ved +10°C 14-apr 11:38 B&O OK Ingen lyd (hverken fra CD eller Radio)

PCB 12 kan tilsyneladende ikke lide temperaturtransienter

F-test ved +17°C 14-apr 11:46 B&O N/A Stopper af og tilF-test ved +25°C 14-apr 11:50 B&O N/A Verifikation af opstilling

Rampe ned med 1°/min 14-apr 12:02 B&O N/A OK ved 20°C, OK ved 17°C,

F-test ved +15°C 14-apr 12:41 B&O N/A OKRampe ned med 1°/min 14-apr B&O

F-test ved +10°C 14-apr 12:59 B&O OK Funktion ustabil (skifter mellem lyd eller display)

Rampe ned med 1°/min 14-apr B&O Rampe hastighed passer ikke !

F-test ved 0°C 14-apr 13:22 B&O OK OKRampe ned med 2°/min 14-apr B&O

F-test ved -10°C 14-apr 13:33 B&O OK OK, dog funktion ustabil af og til

Rampe ned med 2°/min 14-apr B&O

F-test ved -20°C 14-apr 13:46 B&O OK OK, dog funktion ustabil af og til

Rampe ned med 2°/min 14-apr B&OF-test ved -30°C 14-apr 14:04 B&O OK OK

Rampe ned med 2°/min 14-apr B&O Radio begynder at "knase" ved -35°C

F-test ved -40°C 14-apr 14:14 B&O OKRadio-del næsten

ubrugelig, grøn LED tændtGrøn LED hører til "Timer funktionen"

Rampe ned med 2°/min 14-apr 14:24 B&OF-test ved -50°C 14-apr 14:35 B&O OK Grøn LED tændt

Rampe ned med 2°/min 14-apr 14:36 B&O Støj ved skift mellem programkilder ved -55°C

F-test ved -60°C 14-apr 14:43 B&O Går ud engang imellemTilbage til ambient 14-apr B&OF-test ved +25°C 14-apr 14:56 B&O OK Display ustabilt ellers OK

Ekstra test ved -55°C 15-apr 14:15 KAS N/A Med nr. 3. Knaser ved ca. -38°C

Efter at P20 testledning var repareret

Lower Operational Temperature Limit LOTL -55°C -35°CLower Destruct Temperature Limit LDTL Ikke fundet Ikke fundet

Resultat

150

DELTA/KAS Varmeeksponering

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

Aktivitet Dato Tid Init. SMPS PCB 12 BemærkningInitial F-test 14-apr 14:56 B&O OK Display ustabilt ellers OKRampe op med 5°/minF-test ved +40°C 14-apr 15:09 B&O OK OKRampe op med 5°/minF-test ved +50°C 14-apr 15:17 B&O OK OKRampe op med 5°/min

F-test ved +60°C 14-apr 15:26 B&O OK OK (dog lidt problemer med display)

Rampe op med 5°/minF-test ved +70°C 14-apr 15:51 B&O OK OKRampe op med 5°/minF-test ved +80°C 14-apr 16:00 B&O OK OKRampe op med 5°/minF-test ved +90°C 14-apr 16:07 B&O OK OKRampe op med 5°/minF-test ved +100°C 14-apr 16:15 B&O OK OKRampe op med 5°/min

F-test ved +110°C 14-apr 16:22 B&O OK OKStoppet ved +110°C for ikke at beskadige testledninger

Rampe ned med 50°/minF-test ved +25°C 14-apr 16:31 B&O OK OK

Upper Operational Temperature Limit UOTL Ikke fundet Ikke fundetUpper Destruct Temperature Limit UDTL Ikke fundet Ikke fundet

Resultat

DELTA/KAS Temperaturcycling

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

Aktivitet Dato Tid Init. SMPS PCB 12 BemærkningStart cycling 14-apr 16:33

Temperaturcycling KAS OK OK10 cykles med 30 min dwell time. Tlow = -55°C, Thigh = +110°C.

F-test 15-apr 08:09 B&O OK OK

Visuel inspektion 15-apr 08:15 B&O

Begyndende stresssymptomer ved lodning af tunge komponenter (endnu ikke kritisk)

Begyndende stresssymptomer ved lodning af tunge komponenter (endnu ikke kritisk)

Resultat

151

DELTA/KAS Vibrationseksponering

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

Aktivitet Dato Tid Init. SMPS PCB 12 Bemærkning

Initial F-test 15-apr 09:44 B&O OK

Nr. 1. virker ikke rigtigt (brummer og reagerer

langsomt). Skiftet til nr. 2 inden vibrationstest

Random 5 grms 15-apr 09:52 KAS OK OK Ca. 15 minutterRandom 10 grms 15-apr 10:06 KAS OK OK Ca. 15 minutterRandom 15 grms 15-apr 10:20 KAS OK Slår fra engang imellem Ca. 10 minutter

Fejlsøgning 15-apr 10:32 B&O N/A

Ser ud til at være omkring stik P20 (data, clock

mm.). P20 testledningsstik ustabilt

F-test 15-apr 10:58 B&O N/A Skiftet til nr. 3 + testledningstik P20 skiftet

F-test 15-apr 11:16 B&O OK OKRandom 15 grms 15-apr 11:18 KAS OK OK Ca. 5 minutterRandom 20 grms 15-apr 11:24 KAS OK OK Ca. 15 minutter

Random 25 grms 15-apr 11:38 KAS C1 + RT1 falder af efter ca. 1 minut

OK Ca. 2 minutter

F-test 15-apr 11:58 B&O Skiftet til nr.2 hvor C1 og RT1 er støttelimet

OK

Random 25 grms 15-apr 11:58 KAS C55 falder af og C54 løs efter ca. 12 minutter

OK Pause efter ca. 1 minut, i alt ca. 12 minutter

Skift til nyt emne 15-apr 12:17 B&O

Skiftet til nr. 3 hvor C55, C54, C21, C22, C1 og RT1 er støttelimet. Nr. 3 virker

ikke i opstillingen. Skiftet til nr. 4 der er støttelimet på

samme måde

OK

F-test 15-apr 12:37 B&O OK OK

Random 25 grms 15-apr 13:09 KAS OK UstabilCa. 3 minutter (i alt ca. 15 minutter ved 25 Grms). Accelerometer nr. 4 faldet af

Random 30 grms 15-apr 13:15 KASL7 knækket halvt af efter

ca. 15 minutter. Repareret og støttelimet

OK Ca. 15 minutter

Random 30 grms 15-apr 14:02 KAS OK OK Ca. 3 minutter. Accelerometer # 4 sat på igen

Random 35 grms 15-apr 14:05 KAS Fejler OK Ca. 6 minutterHerefter lav temperatur af PCB 12 # 3

Random 35 grms 15-apr 14:18 KAS (ikke med) OK Accelerometer # 2 og # 4 falder af. Ca. 10 minutter i alt

Random 40 grms 15-apr 14:29 KAS (ikke med) OK Ca. 10 minutterRandom 45 grms 15-apr 14:39 KAS (ikke med) OK Ca. 12 minutterRandom 50 grms 15-apr 14:52 KAS (ikke med) OK Ca. 10 minutterRandom 55 grms 15-apr 15:02 KAS (ikke med) OK Lidt ustabilitet i lysRandom 60 grms 15-apr 15:12 KAS (ikke med) OK Ca. 10 minutter

Random 100% ! 15-apr 15:22 KAS (ikke med) OK (første produkt på 100% !!!)

Ca. 61-64 grms. Ca. 10 minutter

Visuel inspektion 15-apr 15:37 B&O

C97 og C107 faldet af. Monteringsvinkel på netstiksskinne ved netskinne knækket

25 Grms (C1, C21, C22, C54, C55, RT1)30 Grms (L7)

Vibration Destruct Level KAS 35 Grms ca. 65 grms (kondensatorer)

Resultat

Operational Vibration Level Ikke fundetKAS

Eksponering udført med random vibration i 6 akser. 10-15 minutter ved hvert niveau. 5 grms step

152

DELTA/KAS Kombineret vibrations- og temperatureksponering

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

Aktivitet Dato Tid Init. BemærkningInitial F-test SMPS PCB 12

Kombineret vibration og temperatur cycling

16-apr 08:11 KAS

Ustabilitet efter ca. 8 minutter ved -55°C. CD afspilning virker

ikke efter ca. 10 minutter. Dør helt

efter ca. 7 minutter ved +110°C

"Sædvanlig knas" på vej ned i temperatur. Vil ikke starte op efter power off ved -55°C.

Kan ikke spille CD ved slutningen af T = 110°C

1 cykle med 15 min dwell time. Tlow = -55°C, Thigh = +110°C. Vibrationsniveau 20 grms.

Funktionstest 16-apr 08:50 B&O OK OK

Kombineret vibration og temperatur cycling

16-apr 08:53 KAS

CD afspilning stopper efter ca. 5 minutter ved -55°C. Støttelim (Hot-melt) svigter ved den høje

temperatur

Radio "dør" efter ca. 4 minutter ved -55°C

1 cykle med 15 min dwell time. Tlow = -55°C, Thigh = +110°C. Vibrationsniveau 30 grms.

Funktionstest 16-apr 09:36 B&O Virker ikke (C55 knækket af)

OK

Kombineret vibration og temperatur cycling

16-apr 09:36 KASEr med, men virker

ikke

Stadig problemer undervejs (men ingen

"nye")

1 cykle med 15 min dwell time. Tlow = -55°C, Thigh = +110°C. Vibrationsniveau 40 grms.

Funktionstest 16-apr 10:16 B&O

Virker ikke (flere komponenter der er

støttet limet knækket af)

OK

Kombineret vibration og temperatur cycling

16-apr 10:19 KAS Er med, men virker ikke

Stadig problemer undervejs (men ingen

"nye")

1 cykle med 10 min dwell time. Tlow = -55°C, Thigh = +110°C. Vibrationsniveau 50 grms.

Visuel inspektion + funktionstest 16-apr 10:57 B&O

C11 og U2 knækket af

Funktion OK, men C89 knækket af.

Antennestik knækket. Monteringsvinkel på netskinne knækket

Resultat

153

DELTA/KAS Resume

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

SMPS PCB 12 Bemærkning

LOTL -55°C -35°C Lower Operational Temperature Limit.

LDTL Ikke fundet Ikke fundet Lower Destruct Temperature Limit

Svaghed Støj ved skift af programkilder Radio "knaser" i lyden

UOTL Ikke fundet Ikke fundet Upper Operational Temperature Limit.

UDTL Ikke fundet Ikke fundetUpper Destruct Temperature Limit

Svaghed (stoppet ved +110°C pga. testledninger)

(stoppet ved +110°C pga. testledninger)

OVL25 grms (5 komponenter)

30 grms med L7) Ikke fundet Operational Vibration Level

VDL ca. 35 grms ca. 65 grms Vibration Destruct Level

Svaghed Montering af C1, C21, C22, C54, C55, RT1 og L7

Montering af C97 og C107. Moneringsvinkel på netskinne

Temperatur cycling(-55°C/+110°C, 30 min.dwell10 cycles)

Svaghed

Begyndende stresssymptomer ved lodning af tunge komponenter (endnu ikke kritisk)

Begyndende stresssymptomer ved lodning af tunge komponenter (endnu ikke kritisk)

Kombineret vibration og temperatur10, 20, 30, 40 og 50 grms,-55°C og +110°C

SvaghedProblemer med CD afspilning

ved lav temp. Montering af C11 og U2.

Montering af C89. Monteringsvinkel på netskinne,

Antennestik knækket i ene side

Bemærkning: Der bør udføres en detaljeret visuel inspektion af alle emner for at afdække eventuelle andre svagheder

Eksponering

Kulde

Varme

Vibration

154

DELTA/KAS Konklusioner efter overordnet visuel inspektion udført på DELTA

HALT test af moduler til BeoSound 1 og BeoSound3000 udført for Bang & Olufsen a/s

DELTA sag nr. E501018 A

Formål At finde de svage punkter for SMPS til BeoSound 1 Her er der plads til kundens's kommentarer

Mulig årsag Aktion

Fundne svagheder Ja Nej (evt. henvisning til fejlrapport etc.) Ja NejStøj ved skift mellem programkilder

RT1 falder af

C21, C22, C54 og C55 falder af

L7 falder af

C11 falder af

U2 knækker af

CD afspilning stopper ved kav temp./vibration

Formål At finde de svage punkter for PCB12 til BeoSound 3000

Mulig årsag Aktion

Fundne svagheder Ja Nej (evt. henvisning til fejlrapport etc.) Ja NejRadio "knaser" i lyden (ved lav temp.)

C97 og C107 falder af

C89 knækker af

Monteringsvinkel på netskinne knækker af

Antennestik knækker af

Relevant RE-HALT

Relevant RE-HALT

De testede moduler bør underkastes en detaljeret visuel inspektion