THASOS. Service manual.doc

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THASOS 4182

SERVICE MANUAL

MICRELEC SA THASOS 4182 SERVICE MANUAL - PAGE 1/14



INTRODUCTION

Welcome to THASOS SERVICE MANUAL.

This short manual is aimed at service technicians. It is assumed thatthe service technician is already familiar with the THASOS basicfunctions so that he can perform an operating test of the machine.

The THASOS basic functions are described in the INTRODUCTORYUSER MANUAL. All service technicians may refer to this manual fordetails on the machine operation.

The aim of the present manual is to educate the service technician tobe able to recognise all replaceable modules in the ECR and be able todiagnose which is the most likely module to cause a given malfunction.

The aim of the service technician visiting a customer is to be able to fixa problem by quickly replacing on site one (or more in rare cases) of malfunctioning modules. Doing so, he will be able to deliver a workingmachine within minutes.

The picture below presents all functional modules (or subassemblies)that make up the THASOS ECR. The picture was taken after atechnician has unscrewed the sealed screw at the top (fiscal seal) andthe four screws at the bottom that hold top and bottom case together.Right after that, the technician has moved the top case over andbehind the bottom case and then moved the keyboard assembly at thefront of the bottom case, placing it top side down to reveal allmodules.

For details on opening up the case for servicing the internal parts,please refer to the following chapter, OPENING UP THE CASE.

For details on the function, debuging and probability of any givenmodule to be malfunctioning please refer to the following chapter,MODULE LINE UP.

For details on how to power up the ECR again after replacing a faultymodule, please refer to the chapter named RESETING THE ECR.




MAINBOARD

MODULE :The heart of thesystem, themainboard module,drives all other modules and runs theapplication fiscalsoftware. Themainboard can bereplaced on site, asany other module,with minimum effort.

KEYBOARD

MODULE:

Here shown topside down, the

keyboard module isa subassembly of

70 raised top keys

that connects to

mainboard using astandard 20pin IDC

THASOS 4182FUNCTIONAL MODULES

DISPLAY MODULEThe display module

consists of one

customer LCD display

and one operator LCDdisplay. These are the

only modules attachedon the upper part of

the case. Both LCDs

connect to theMAINBOARD via one

flat cable connector.

BACK CONNECTORSMODULE: This is a

PCB that carries the

serial RS232 and

drawer connectors(also the Ethernet

connector if that optionexists)

POWER SUPPLY

MODULE: this moduleconsists of AC two pole

on/off switch and afilter/switching power

supply unit that takes

150-240VAC as input

and delivers 12VDC /50W output.

FISCAL MEMORY

MODULE: this is the

fiscal PROM memoryunit, normaly covered

with resin that

completely seals themodule in the box

provided in the case.

PRINTERS MODULE PAPER WIND MODULE

The 2 thermal printers (receipt and journal) This module is an electric DC motor drivenare both assembled on one PCB that connects Mechanism to wind the journal paper both mechanisms to the mainboardusing a single 20 pin flat wire




OPENING UP THE CASE

There are just 6 screws to remove to open up the case. For securityreasons,though, you can not unscrew the top screw unless you breakup the special fiscal seal that is covering up the top screw 1. Only aqualified technician should attempt this. Follow these steps:

1. Unscrew the top sealed screw as shown in picture. To be able tounscrew this you must first break the fiscal screw. Use the tip of a screwdriver or any other sharp object to remove the resin orany other seal material that is used.

CAUTION : Only qualified technicians shall break the fiscal seal.Qualified technicians carry with them approved sealing material torestore the fiscal seal after repair.

2. Unscrew the four bottom screws as shown in picture.




MODULE LINE UP

Once the case is opened the technician can place the top cover, whichcarries the displays, at a distance behind the bottom case. The flatcable connecting the top displays with the mainboard is enough todisplace the cover at a logical distance so all interior is easilyaccessible.

Then the whole keyboard assembly can be raised from its seat andplaced at the front of the bottom case as shown in the picture abovewithout removing the flat wire from its mainboard connector.

As you may see on the picture above, all eight functional modules arethus made available for inspection and change.

Here is a short description of each one:

1. MAINBOARD MODULE

What does it do?The mainboard is the heart of the system, driving all other modules

and storing all data and parameters. The mainboard contains themain CPU, the application software in firmware, all data andparameters in CMOS RAM which is backed up with a NiCd battery,and generally all necessary electronics to drive all peripherals.

When to change it?The mainboard should be changed when there is power (you caneasily measure it using a voltmeter on the power output of the PSUmodule) but the ECR is not responding to any operation or theoperation is totally erratic.

Also, the mainboard should be changed when you can operate theECR but you get totally wrong printouts (like wrong numbers intotals, distorted graphics or upredictable printings).

Obviously, the mainboard should be changed when everything elsefails!

How to change it?




To remove the mainboard you follow two steps:

Step 1: Remove all connecting wires marked with a green dot inthe following picture. The green dots are numbered 1 to 7 for thetotal of the connectors existing on board. These are:

DOT 1 is the power connector, oriented by the mating connectorDOT 2 is the paper winding connector, oriented by the mating conDOT 3 is the printer’s connector, oriented by the mating conDOT 4 is the keyboard connector. Observe the orientation shown inpicture since there is no oriented mating connectorDOT 5 is the RS232 connector. Observe the orientation shown inpicture since there is no oriented mating connectorDOT 6 is the displays connector. Observe the orientation shown inpicture since there is no oriented mating connectorDOT 7 is the fiscal memory connector. Observe the orientation

shown in picture since there is no oriented mating connector

Step 2: unscrew the four screws that are holding it at the bottomcase as shown by the red arrows above.

Repeat above steps in reverse order when placing a new (and

tested) mainboard. To power up the new mainboard, follow theinstructions on following chapter, RESETING THE ECR.

How rare is it?Due to its complexity, you will encounter mainboard malfunctionsmore often than any other module malfunctions. This means thatthe mainboard module is suspect for malfunction in many caseswhere the cause is not obvious.




2. KEYBOARD MODULE

What does it do?The keyboard module is the array of keys used to operate the

machine. It has no electronics, only a PCB and 70 switches / keysconnected to the mainboard via a flat cable wire.The keys are connected in a 9X9 scan matrix driven by a dedicatedmicrocontroller on the mainboard. Their function is to close a circuitbetween scan and input lines when pressed.

When to change it?Usually one or two keys present problems in operation due to wearfrom frequent use. The modular approach for the service of CRETAcalls for replacing the whole keyboard module instead of the single

malfunctioning key. This allows for easy on site repair, while themalfunctioning unit can then be repaired at the service lab later.

How rare is it?Because of its mechanical nature, some keys may present problemsafter a long time of use or when liquids are spilled onto them. Theirexpected life is over a 1,000,000 contacts, so even if you use a key1000 times per day, you can expect that key to last for more thanthree years.




3. PRINTER MODULE

What does it do?The printer module is a complex one since it is an assembly of onebase PCB and two thermal printer mechanisms. You can replace

just one of the two printers or the whole assembly depending onthe nature of the malfunction.

The printer on the left is used to print out the journal and theprinter on the right is used to print out the receipt. Both printerswork in parallel and the two printouts are identical. Sometimes,because of the parallel driving, the malfunction of one mechanismaffects the printout of the other.

When to change it?

If you notice a portion of the printout missing in one printer whilethe other one still prints accurately, then the first printer needs tobe replaced.

If you get continous paper out messages even though you havepaper installed you may be facing a printer mechanism malfunctionor a mainboard malfunction. Try to replace the printer mechanismfirst and if that does not change replace the mainboard.

How to change it?The following picture shows the printer module:

First, observe the blue arrows. In journal printer, marked with thegreen dot 1, the blue arrows show the correct, operational positionof the thermal head. The green plastic is at its lowest position. Onthe right, at the receipt printer marked with the green dot 2, theblue arrows show the head off position, that is the non-operationalposition of the green plastic thermal head.




The service technician should always make sure that the heads areat on position before doing anything else.

To replace just one mechanism unscrew the relative screws shownby the yellow arrows at the picture above. Then pull out the ribboncable marked with the green dot in same picture.

If you need to replace the whole assembly, then you must unscrewthe screws marked with the red arrows in the picture.

How rare is it?The FUJITSU thermal printers are extremely reliable. On aninstalled base of around 50,000 units we get about 1 or 2 units permonth that need replacement. This may vary, though, dependingon the quality of the thermal paper used, service time and

conditions of operation.The thermal head has a life of approximately 50km of paper or100million dot lines, whichever comes first. This is practice maymean that in cases of heavy printouts you may need to change themechanism in about three years service time.

4. PAPER WIND MODULE

What does it do?The paper wind module is an electromechanical assembly at theback of the journal printer that serves to roll the journal paper.It consists of an electric DC motor, driven by the mainboard, anelastic belt and gear to exert a tension at the journal paper roll.

When to change it?You may need to replace the DC motor if you notice you don’t getany movement of the motor even if you have disengaged the belt.You may also need to replace the elastic belt if it is worn out.

How often is it?The DC motor is not stressed at all and you will very rarely meetany problems. The elastic belt is also very long life, but eventualyyou may need to replace it.




5. DISPLAYS MODULE

What does it do?The displays module is the only one of the modules that isassembled at the top case of the ECR. It is a complex moduleconsisting of both the operator display unit and the customerdisplay unit. Both units are driven in parallel, so you must seeexactly the same text on both screens.

When to change it?If one of the screens fails to show a correct text or doesn’t showanything at all while the other one is displaying correctly, you knowyou must replace the faulty one.

If both screens fail to show anything at all then you may have aproblem not with the display module itself but with the mainboard.

How rare is it?The LCD screens rarely present problems, but one must keep inmind that those screens are sensitive to extreme heat or cold andpermanent damage may result if exposed to such conditions.

6. BACK CONNECTORS MODULE

What does it do?This is the plastic cover at the back of the ECR carrying the twoRS232 ports and the drawer connector. If the optional ethernetboard is installed, then the back panel carries also a UTP standardethernet connector.

When to change it?When you have a problem with RS232 or drawer operation and can

not be remedied by replacing the mainboard.

How rare is it?Since only electromechanical components (connectors) are presenton this module, malfuntions due to this module are extremely rare.




7. POWER SUPPLY MODULE

What does it do?The power supply unit (PSU) together with the necessary AC cables

and mains on/off switch comprise the power supply module.This module provides all power to the ECR and any malfuntion inthis module results in total failure to operate.

When to change it?Power Supply failures are the easiest to diagnose: you turn on theECR and nothing happens. You open the case and, using avoltmeter, you measure the voltage across the black and red wirescoming out of the PSU. If your reading is 0V or fluctuating then youhave a problem with PSU.

In some cases, though, the problem is not with the PSU at all. ThePSU has a built-in short circuit protection that prevents the powersupply from starting up if there is a short circuit present. So insome rare cases you may have a short circuit on the mainboard orthe printers and this is causing the PSU to stop from starting up.

To distinguish between those two situations, remove the black/redcable from the PSU and then measure the voltage across theconnector, prefferably with an ohmic load in place. If you get close

to 12VDC under load, then the PSU is likely to be ok and you shouldlook for a short circuit somewhere.

How often is it?This module is the second most probable to malfuntion modulebesides the mainboard for two reasons: one, because it is thesecond most complex electronic module in the ECR and second,because it must handle all mains surges and interference which, inextreme cases, may damage its circuitry.




8. FISCAL MEMORY MODULE

What does it do?Fiscal memory module is the most critical component in a fiscal

cash register as it is this that keeps all tax totals. The fiscal memorymodule is kept always separately from the mainboard and is alwaysglued at the bottom case with a resin.

Normally you have no access to this module and, once an error infiscal memory is detected, the ECR will stop operating automaticaly,displaying a message like ‘FISCAL MEMORY ERROR’.

When to change it?

Actually in fiscal countries the fiscal memory is never changed. If apermanent failure is detected, then a special procedure defined bythe local tax authorities must be followed.

The service technician is adviced to perform first a full system reset(as described in next chapter) and see if this remedies the problem.If not, then he must try out changing the mainboard, in case thefiscal error is caused by mainboard malfunction and is not located inthe fiscal module. If everything fails, then the fiscal module is inerror.

How rare is it?Fiscal memory errors are extremely rare. Because this is the mostimportant component in terms of fiscal law, special care has beentaken to protect as much as possible the fiscal memory. For theTHASOS model the statistical data show the occurrence of about 1such error per 10,000 units per year.




RESETING THE ECR


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