SAFETY INFORMATION CAUTIONSafety information is contained in the appropriate Service Data. All product safetyrequirements must be complied with prior to returning the instrument to theconsumer. Servicers who defeat safety features or fail to perform safety checks maybe liable for any resulting damages and may expose themselves and others topossible injury.

All integrated circuits, all surface mounted devices, andmany other semiconductors are electrostatically sensitiveand therefore require special handling techniques.

First Edition - First PrintingCopyright 2005 Thomson, Inc.Trademark(s)® Registered Marca(s) Registrada(s)RCA and the RCA logos are trademarks ofTHOMSON S.A. used under license toTTE CorporationPrinted in U.S.A.

Prepared byThomson, Inc for TTE Technology, Inc.Technical Training Department, INH905PO Box 1976Indianapolis, Indiana 46206 U.S.A.

FOREWORDThis troubleshooting guide is designed to aid the service technician in troubleshootingthe ITC008 chassis. It will provide general information on circuit operation,troubleshooting procedures, and some common failures reported to Thomson’sTech-Line.

The troubleshooting procedures may include circuit verification procedures used toeliminate a circuit area from the troubleshooting steps. When using the circuitverification procedures, care must be exercised to prevent further damage to the set.

Reference material referred to by this manual includes:

• ESI service data

• Training Manual

• Parts Finder (for Part Numbers)

Page 4

ContentsFOREWORD .................................................................................... 3SAFETY INFORMATION CAUTION ................................................. 3Troubleshooting Fundamentals ..................................................... 5ITC008 Shutdown............................................................................ 7 XRP EHT Shutdown ................................................................... 8 Over Voltage / Over Current Shutdown (Pincushion).............. 8 +12Vr Shutdown......................................................................... 8 I2C Bus Communication Shutdown ......................................... 8 Shutdown Troubleshooting Flow Chart ................................... 9ITC008 Power Supply Troubleshooting....................................... 10 Dual Voltage Regulator IP030 ................................................. 12IT008 Deflection Troubleshooting ............................................... 13 Vertical Deflection Troubleshooting ....................................... 14 Horizontal Defleciton Troubleshooting .................................. 16 Alternate Vertical Troubleshooting Information .................... 18ITC008 Pincushion Shutdown Troubleshooting ......................... 19

Page 5

This troubleshooting guide covers several circuit areas. These areas are related todead set or shutdown type symptoms only.

Circuit areas are:

• Power Supply

• Deflection (Horizontal and Vertical)

• Pincushion Shutdown

• Shutdowns

Troubleshooting FundamentalsOne definition of troubleshooting is the diagnosis and repair of malfunctions inelectronic equipment using “Logical Analysis” and “Systematic Checks”. The keyphrases of this definition are Logical Analysis and Systematic Checks. Without theapplication of these two principles, troubleshooting complex electronic circuitry is, atbest, a hit or miss proposition. It’s also known in some circles as “Shot-Gunning”.

It’s important to remember that troubleshooting is something of an art form and is asmuch a mental process as it is checking waveforms and voltages. In order toeffectively troubleshoot electronic equipment there are several skills the technicianmust have.

The technician must have:

• A solid understanding of basic electronics. He or she must understand howa transistor, resistor, capacitor, coil, diode, etc. work. They must alsounderstand AC and DC circuits. Even with the best test equipment, withoutthis basic understanding of electronics, the technician is only guessing as tothe cause of a malfunction.

• A basic knowledge and understanding of how all the parts of theinstrument function together and how they affect each other. Thisoverview of system operation is necessary in order to understand how theindividual circuits can affect the overall operation of the equipment. Thisis necessary in order to be able to associate a malfunction or symptomwith a circuit. In other words, could the suspected circuit cause thespecific type of symptom seen?

Page 6

When discussing troubleshooting techniques or principles there are a couple ofthings that should be kept in mind. First, no one can teach a technician the best wayto troubleshoot. Troubleshooting is a skill that’s very individualistic. This means thateach and every technician will troubleshoot the same problem or malfunctiondifferently. That doesn’t mean one method is right and the other is wrong, just thatthere are many different ways of solving a problem and that’s what troubleshootingis all about….Problem Solving. However, there are some basic steps and guidelinesthat can help a technician get started. A skilled technician will develop his or her ownstyle with time and experience.

In most cases troubleshooting can be divided to three basic levels or steps:

1. SECTIONALIZE

2. LOCALIZE

3. ISOLATE

SECTIONALIZE; determine which major functional group or section of the instrumentcontains the fault. Generally, most problems can be sectionalized by carefullyanalyzing the symptom.

LOCALIZE; determine which major circuit within a section can or cannot cause theexhibited symptom. This usually requires checking major or key test points.

ISOLATION; find and repair the stage and/or component that has failed. This steprequires detailed measurement and monitoring of signals and voltages within thesuspected circuit area.

To quickly and efficiently diagnose a malfunction, the technician should follow a setsequence of steps each time he services a piece of equipment. There are five (5)basic steps in troubleshooting or symptom analysis.

1. Physical Inspection

2. Operational Check

3. Sectionalize

4. Localize

5. Isolate

Page 7

Following these five simple steps and having a basic understanding of electronicsalong with how the equipment works will organize the technician’s troubleshootinginto a logical pattern or sequence and increase their effectiveness as a troubleshooter.Remember, these are only principles and can be interpreted in many different ways.Also, troubleshooting is a very unique skill and is learned by doing. All theseprinciples and concepts can be applied to servicing virtually any type of product orequipment. The five steps of troubleshooting may seem obvious to some or complexto others but with time and experience they will become second nature

ITC008 ShutdownShutdown consists of:

• An XRP circuit that monitors the heater pulse from pin 12 of LL05.

• Over voltage and over current shutdown for pincushion

• +12Vr shutdown

• I2C Bus Communication shutdown

Determining which shutdown circuit to troubleshoot is the key. There is no quick wayand from past experience, one just needs to start the process of elimination andeliminate them one at a time.

Each shutdown has it’s own “trigger”. This “trigger” is what causes the shutdown tooccur. More then one “trigger” my feed into a single shutdown circuit. These typesof shutdowns seem to be the most difficult to troubleshoot. For example, in theITC008 pincushion shutdown over current and over voltage are on the same linefeeding the shutdown of horizontal drive. In this same shutdown circuit, feedbackfrom the IHVT (LL005) is used to kill drive signal while energy is still being transferredfrom LL005. In this shutdown there are three signals that can kill horizontal drive andshutdown the set. Knowing how to disable each will aid in troubleshooting what“trigger” is causing the shutdown.

This section will provide troubleshooting tips on how each shutdown “trigger” can beisolated in a safe manner. In some cases there is no way to isolate the triggertherefore, some understanding of the shutdown will help logic out the “trigger”. Othertimes it is trial and error.

Page 8

XRP EHT Shutdown

Use extreme caution when doing this procedure!!

Start by disconnecting the CRT anode lead and CRT socket. Then locate JL905 atgrid location 8,UU on the main CBA. Unsolder one end. This disables both the EHTand excessive current shutdown for high voltage. Use caution with XRP EHTshutdown disabled and keep on-times to a minimum.

Over Voltage / Over Current Shutdown (Pincushion)

This is by far the easiest to disable. The feed back information that causes shutdowncomes through connector BF001. By unplugging this connector the shutdown isdisabled.

+12Vr Shutdown

This is not a typical shutdown circuit but more a lack of run voltage issue. The +12Vris used as the run voltage for Horizontal driver amp TL033. If this voltage is missingTL033 will start but never run. Supplying the +12Vr from an external DC sourceverifies the +12Vr as the problem. This voltage should be supplied to the Cathodeof DL012 and referenced to cold ground while the set is pulsing or trying to start.

I2C Bus Communication ShutdownWith this shutdown it is a trial and error situation. Error codes are logged forcommunication shutdown but can only be read if the set is operational. Knowing thatthe Tuner, MAV CBA, and Alert Guard CBA are the only communication problemsreported it is safe to use the process of elimination for this shutdown.

The Alert Guard CBA is the only one that is of Plug and Play nature. Both the Tunerand MAV CBA will cause shutdown if connected or not. Therefore; trying the Tunerand the MAV are by trial and error.

Page 9

Shutdown Troubleshooting Flow Chart

The above flow chart is used to troubleshoot a dead set or shutdown condition. Thischart and the troubleshooting sections found in this guide cover those scenariosfound during calls to Tech-line. They do not cover all possible scenarios, only themost common or unique ones.

Apply AC power andpress the power switch.

Does the set Pulse 3 timesand quit or Cycle every 5 sec.

continuously

Pulse at 5 SecIntervals

Cycles 3 Times

Disconnect the AlertGuard Module.

Try to turn on theset. Does the set

start?

Suspect the AlertGuard Module

Disconnect thePincushion Connector

BF001

Try to turn on theset. Does the set

start?

TroubleshootHorizontal Deflection

Troubleshoot PowerSupply

Troubleshoot SystemControl

Communication I2CBus

Tuner and MAV?

Suspect thePincushion Module

Try to turn on theset. Dead or

Pulsing?Dead

Pulsing

YES

NO

YES

NO

Does the set haveAlert Guard? NO

YES

Page 10

ITC008 Power Supply Troubleshooting(Dead Set, Power supply voltages missing or incorrect)

NOTE: DP027 will short whenever feedback is lost or an excessive load on thesecondary of LP003 is present. This will shut down the power supply. IF DP027 isshorted, check FZP61. If FZP61 is open, check the +13.1V for excessive load andcheck the feedback circuit (IP001, TP022, and IP050) for proper operation.

1. Check RAW B+, if not OK check the full wave bridge rectifier DP002/003/004/005and it’s associated components.

2. If RAW B+ OK, check the current sensing resistor RP020. If open, this wouldindicate there has been a severe over current condition between the drain andsource of TP020. Check and replace all defective active components on theprimary side of LP003. Check for excessive loads off secondary of LL03 beforereapplying AC power.

3. Check for DC voltage and waveform on the gate of TP020. A waveform, like theone on page 11, indicates the oscillator is running. If there is no waveformunsolder the drain of TP020 and check for 7.8Vdc on the gate. 7.8Vdc on the gateof TP020 indicates start-up circuit is working go to step 5. If a waveform is presenton the Gate of TP020, the primary switching of the supply is working.

3

2

9

5

RAW B+

1

23

41

2

3

+13.1V

Ω0.27

GD

S

1

+6.3Vs

+21.5V

+126V

+19.5V

Pwr GoodTP193,192

PG1

11

10

12

13

14

15

1618

IP001

DP030RP155

IP050CP040

RP041RP026

RP040

DP040

RP030

RP006

RP007

DP005

DP002

DP004

DP003

FP001

CP008

TP020

DP033

RP021

RP033

RP031

RP029

RP023 RP027

TP025

RP132

TP023

TP022

RP028

RP125DP023

RP020

DP025,026

LP003 DP080

CP080FZP603.15A

FZP93500mA

FZP613.15A

RP066

DP093

CP094

CP064DP063

DP097

RP056

RP054 RP158

Slow StartRP037,038

DP037CP037,038

CP039

CP022

TP052

DP057

RP057

RP151

BurstMode

IV001 pin 63

CP062DP202

CP206

DP061

CP024,025DP027

RP052

BeamCurrentSense

8.2V

27V

15V

9.1V

27V

Page 11

Start-up Circuit Test:

Working unit voltages with the Drain of TP020 open: (HOT GND Reference)

• Gate = 7.8V

• Startup ckt = 8.9V (Measured on TP025 (E))

• TP025 C = 8.0V, E = 8.9V, B = 8.3V

• Junction of RP006 and 007 = 32.4V

4. If DC on gate of TP020 is wrong, check TP025, DP027, DP023, RP006, andRP007 and replace if suspect. Hint: 27V on the emitter of TP025 indicates thatthe base circuit of TP025 is open. Check DP023, RP125, RP132, or open circuitto pin 3 of LP003. If there is 0V on the emitter of TP025 and DP027 is shorted,check the regulation feedback circuit associated with IP001 and IP050.

5. If no waveform on gate of TP020 (DC OK), check TP022, TP023 and theirassociated components. Replace all transistors if one has failed or is suspect.If TP020 has failed more than likely the other transistors have been stressed andthe circuit will self-destruct again when plugged into 120 AC.

6. If TP020 checks OK (with primary circuit pulsing), check IP050 (ReferenceRegulator) and IP001 (Opto Coupler) and their associated components. Alsocheck for excessive loads of the secondary of LP003.

Gate of TP020 Waveform Stby Mode

DeviceResistance

to Cold GNDDP080 45.7KDP061 1.4MDP093 5KDP063 7K

Resistance Chart for Power Supply

Page 12

Dual Voltage Regulator IP030

There are two output voltages from IP030 but only one is switched. Pin 4 controlsthe output on pin 8 (7.9V). When pin 4 goes high, there should be 7.9V on pin 8. Thisis easy to check by simply removing (unsoldering) pin 4 and checking the output. Ifvoltage is present on pins 1 and 2 then pin 8 should be 7.9V if IP030 is workingcorrectly.

The other output on pin 9 is 3.3V. This voltage is used for System Control standbyB+ and Pin 6 of IP030 is the reset voltage for IV001 (SysCon). When power is firstapplied, IV001 turns on the dual regulator (IP030) for a short period of time. Duringthis time Degauss is energized and pin 8 of IP030 is switched on supplying the 7.9V.No relay click could indicate IP030 3.3V problem.

IP030 Troubleshooting

1. Check for 13.1V on pin 1 and 2 of IP030. If the voltage is correct go to step2. If missing or not correct troubleshoot standby power supply.

2. Unsolder pin 4 of IP030 and check for 7.9V on pin 8. If the voltage is present,go to step 3. If the voltage is low or missing suspect IP030.

3. Reconnect pin 4 and check for 3.3V on pins 6 and 9. If present, go to step4. If the voltage is low or missing suspect IP030.

4

IP030

DualReg.

8

9

6

Reset

+7.9Vs

+3.3Vs

12 3

IP311 2

+5Vs

1

IV001

LL05

33Horiz Out Horiz

Drive/Out

Pwr ON

14

+181Vr

+33Vr

+12Vr

-12Vr

DH0133V

63

Power SupplyControl

IP01,IP50

+13.1Vs

Burst

Hi = Burst & DAM ModeLo = Energy Mode

TP52

RP57

DP57

RP153

RP151

9.1V

DP36CP66

RP166

FZP66

+VCC

+7.9Vs

CRT

Vertical

Tuner

60

5456

TR02 ResetSwitch

Page 13

4. With pin 4 of IP030 connected, monitor pin 8 and press the power switch. If7.8V momintarly comes up, system control and regulator are workingcorrectly, suspect a Horizontal startup problem. If there is no change on pin8 troubleshoot system control.

ITC008 Deflection Troubleshooting

In order to troubleshoot deflection we must first understand where the signals aregenerated. In the ITC008, IV001 (TV Processor) is used to generate both the Verticaland Horizontal drive signals. The generation of these drive signals depends onseveral external circuits and proper operation of IV001.

First, being system control, IV001needs to have VCC (Stby), GND, OSC, andRESET to function. Next, some sort of user interface (Remote or FPA) to tell IV001what to do. IV001 also needs a set of instructions to perform the expected command.This instruction is in the form of “DATA” found in the EEPROM (IR001). The “DATA”is used to set up registers in IV001. These registers include Horizontal timing,Vertical timing, and shutdown settings. Transfer of "DATA" happens each time theset is turned on. Failure to properly transfer the "DATA" will result in a dead setcondition.

This troubleshooting section assumes certain sections of IV001 are working correctly.These sections are System Control and Signal Processing.

IV001TV Micro

Clk/Data2,3

5,6

IR001

EEPROM

6 7 64KB/LED IR

BR001to Front Panel

8 +5Vs

14 +7.9VsD

61 +3.3V VDD

RESET60

+3.3V VCCD Core

54,56

1 PWR ON

39

12,18,30,41,57

GND

58,59

QV00158

59

57 OSC GND

IN

OUT

33

36

Horiz Out

XRP EHT

PLL Ckts15, 19, 16, 17

21, 22

VDrive

Page 14

Vertical Deflection Troubleshooting(No Vertical Deflection)

Setup: Remove CRT Socket, apply AC power and turn on set. When troubleshootinga Vertical deflection problem where the set is operated without deflection it iscustomary to remove the CRT socket(s) to prevent the CRT from being burnt.

1. Check for –12V on pin 4 of IF001 referenced to cold ground. If missing suspectDL010 and RL010 or a problem with the –12V supply. If correct proceed tostep 2.

2. Check for proper waveform on pins 1 and 7 of IF001. These waveforms aregenerated by IV001. If not correct, troubleshoot IV001 vertical section orsuspect EEPROM alignment data corruption. If waveforms are present,check for 48V P-P on pin 5 of IF001. If present IF001 is working and problemis in the yoke circuit. If not go to the next step.

3. Compare the voltage found on pin 2 with that found on pin 6 of IF001. Thesetwo voltages should be about .3V different. If they are equal, DF010 shouldbe replaced.

4. Check for –10.3V on pin 3 of IF001. This is the boost circuit for IF001. Whenthis voltage is missing suspect IF001, CF010 and DF010. If correct IF001 isworking and problem is in the yoke circuit.

Hint: If set is shutting down and removing DL062 allows the set to operate with outvertical deflection, suspect IF001, DF010, and CF010. These are the most commonfailures of the Vertical circuit causing the set to shutdown. Also check the +12Vrcircuit (RL012 and DL012) off pin 6 of IHVT (LL005).

NOTE: Settings in the EEPROM (Vertical) can also cause shutdown. Misalignmentof Vertical Slope (parameter #06) and Vertical Amplitude (parameter #08) can causethe protection signal from the E/W module to activate and shutdown the instrument.

To correct for this problem, temporarily disconnect BL101on the E/W module torestart the instrument and reset both parameters.

Page 15

IV001

21

22

14 PWRAMP

IF001Vertical Output

51

7

4

2 6 3

RV06 RF02

DF02

RV05

DF03

RF03

RF04

RF06

CF05 DF10 CF10

DF101

DF102

RF101

CF101

DF0156V

RF08 RF09

CF09

RF07

CF08

BF002

RF102Beam Current Limit

+7.9Vs

-12Vr +12Vr

-12Vr

BF001

toPincushion

Vcc

VDriveA

VDriveB

Page 16

Horizontal Deflection Troubleshooting(No Horizontal Drive)

1. Unsolder collector of TL35 (Horizontal Output Transistor).

2. Monitor the base of TL35 and press the power switch. The set will cycle untilpower is pushed again. A horizontal drive pulse should be present at the baseof TL35 while it is cycling.

3. If a drive pulse is present on the base of TL35, IV001 and the driver circuit areworking correctly. The problem is off the collector of TL35. Suspect Yoke,Yoke return circuit, pincushion, LL05 and the secondary side of LL05.

4. If the drive pulse is missing check for drive at pin 33 of IV001. If missing,suspect CV004, CV005, CV006, CV007, CV008, and RV001 components offof pins 15,16,17, and 19 of IV001. Corrupt data in the EEPROM could alsoprevent horizontal drive.

5. If drive pulses are present at pin 33 of IV001, check for them at the emitter ofTL031. If they are missing, disconnect DL062 and recheck. Drive pulses onthe emitter of TL031 with DL062 removed indicates that drive shutdown hasoccurred (See shutdown troubleshooting section). If drive is present at theemitter of TL031 with DL062 in circuit, check for drive at pin 3 of LL032 (LL033alt). If drive is present at pin 3 of LL032, suspect LL032 (LL033 alt) or aconnection problem with LL032 (LL033 alt). If missing go to next step.

6. Check for 13.0V at the collector of TL033 in standby mode. If missing,suspect RL037 and RL038 or TL033 (shorted). If present suspect DL035,RL034 or the +12Vr source.

NOTE: Pin 33 of IV001 (Horizontal Drive) will have 7.0Vdc when drive is missing.Possible causes of no Horizontal Drive:

• Corrupt EEPROM data

• +VCC missing at pins 14 and 39 of IV001

• Internal OSC off frequency. Capacitors on pins 15, 19, 16, and 17 of IV001effect PLL circuits.

• XRP detected at pin 36 of IV001

Page 17

Anode

Focus

Screen

IHVTLL05

5

8

Heater & XRP

Htr Return

13

12

11

101

9

IV001

33 Hout

CL30

TL31

TL060/061

TL62

TL33

LL32TL35

CL21 DL21

CL23,25,26RL25,26

DL25 LL26

BL005

+126V

RL34

DL35

RL37

RL38

CL35

RL41to 44

+181Vr

+33Vr

33V

-12Vr

+12VrHorizYoke

+12Vr 6

7

XRP

+13.1Vr

Pin 12LL05

1

3 6

4

RL07RL63

RL68

DL62

DL30

RL36

+7.9VsA

RV73

Vcc

14

+7.6VsD

36EHT

Pin 8LL05

Beam CurrentSense to PWR

IP050-3

TL50Buffer

RL12 DL12

CL13

RL10

DL10

CL11

LL40

DL01CL41

RL40

DL40TZ01DZ01,03,05

+7.6VsE

34

BF001

toPincushion

CBA

RL06RF07

from

321

123 BL003from

Pincushion CBA

Feed Back

Page 18

Alternate Vertical Troubleshooting InformationRepeat failure of the vertical output IC (IF001) can be difficult to find and expensive.The following information pertains to troubleshooting the vertical circuit with thevertical yoke disconnected. By unloading the vertical circuit it is possible to makechecks to the vertical output IC with out damaging it.

1. Disconnect the CRT socket and BF002 vertical yoke connector.

2. Using the Voltage chart, check for correct DC on all pins of IF001. If a voltageis not correct see the notes section of the Voltage chart for possible causes.

Pin No. Voltage Notes

1 +.7

Incorrect waveform from IV001 ormissing wavefrom. Check for open orshorted components between pin 21 ofIV001 and pin 1 of IF001. Checkfeedback resistor RF006.

2 +12.2Check for open circuit from +12Vrsource. Remember if the +12Vr ismissing the set will shutdown.

3 -13

This voltage is internally generated byIF001 and pin 4. If missing, suspectIF001 or pin 4 voltage missing.Common parts for incorrect voltageare: IF001, DF010, CF010.

4 -13Check DL010 and RL010 off pin 7 ofLL005. If RL010 is open check forshorts on the -12Vr source.

5 +1.6

This voltage is controlled by IF001 andthe input pins 1 and 7. If pins 1 and 7are correct suspect IF001, RF006,RF009, and RF007. Voltage Highindicates no drive to pins 1 and 7 ofIF001.

6 +11.8This voltage should be lower then pin 2.DF010 is a common failure along withIF001.

7 +.7

Incorrect waveform from IV001 ormissing wavefrom. Check for open orshorted components between pin 22 ofIV001 and pin 7 of IF001.

Page 19

ITC008 Pincushion Shutdown TroubleshootingPincushion shutdown occurs when TL101 (Pin Driver) pulls excessive currentthrough RL111. As the current increases so does the voltage. IL101 pin 12 monitorsthis voltage change and when the voltage exceeds the reference voltage found onpin 13 of IL101, IL101 (comparator) switches states and puts a high on pin 14. Thishigh is sensed by TL061 base turning it on and killing horizontal drive. To defeat thisshutdown circuit and troubleshoot the pincushion circuit, disconnect DL062.

Some of the common failures in the pincushion circuit have been:

• DL101

• DL102

• DL012

1. Verify the set is in pincushion shutdown by disconnecting BF001. If the setstays on, the pin circuit is causing the shutdown. If the set still shuts down theproblem is not with the pincushion circuit.

2. Unsolder DL062 cathode. This removes the shutdown protection. Usecaution when operating the set with DL062 disconnected. Short on-time isrecommended.

1

7

8

141213

32

910

6

IL101

51

2

3

1

2

3

BL101

RL150 RL134

PL143

RL131

RL132

RL107

RL106

PL140

RL108

DL138

RL138

CL138 LL122RL144

CL144

RL145

TL101CL122

DL121

DL122

BL103

DL119

CL12347V

RL113

RL112

RL111

DL118RL118

DL117

RL117

RL141PL141

+12.2Vpin

RL104

RL105

RL136

RL133

RL134

RL137

toCL021

andDL021

RL110

CL110

DL114

DL113

RL114

CL114

+12.2Vpin

Page 20

3. Monitor TL101 (Pin Driver) pin 3 for +18Vdc and 9.5Vp-p waveform and turnon the set. If the voltage is missing or incorrect, suspect he Pincushion CircuitBoard Assembly (CBA). If the voltage is high suspect an input signal problemor incorrect adjustment.

Note: This voltage can reach +130Vdc. Caution should be taken if thisvoltage exceeds +50V. +50V is the over voltage shutdown of the pincircuit. With DL062 disconnected the over voltage shutdown is alsodisabled. Running the set with voltage in excess of +50V can causeadditional damage. Short on time is highly recommended.

Tech-Tip: The Pincushion CBA is a replaceable module, however; troubleshootingthe module to component level can be accomplished. One of the common failureshas been cold solder connections on BL101. An oscilloscope and multimeter arerequired to isolate other problems. Keep in mind that the voltage readings found inthe schematic may not be exactly what your set has. The pincushion circuit hasadjustments for the different screen sizes therefore the voltages and waveforms canbe slightly different. For example: TL101 pin 3 shows to be 18.0V, our test set usedto develop this troubleshooting guide measured 20.8V. An acceptiable range for thevoltage on pin 3 of TL101 would be from +15V to +30V.

1

7

8

141213

32

910

6

IL101

51

2

3

1

2

3

BL101

RL150 RL134

PL143

RL131

RL132

RL107

RL106

PL140

RL108

DL138

RL138

CL138 LL122RL144

CL144

RL145

TL101CL122

DL121

DL122

BL103

DL119

CL12347V

RL113

RL112

RL111

DL118RL118

DL117

RL117

RL141PL141

+12.2Vpin

RL104

RL105

RL136

RL133

RL134

RL137

toCL021

andDL021

RL110

CL110

DL114

DL113

RL114

CL114

+12.2Vpin

Page 21

NOTES

TSG_ITC008