PHILIPS 20LX200125 Technical Service

Philips Consumer Electronics

Technical Service Data

Service and Quality Service Publications Dept. One Philips Drive P.O. Box 14810 Knoxville, TN 37914

Pg. SCHEMATIC DIAGRAMS AND PC BOARDS

1. Chassis Overview

2. Power Supply Schematic - A1

3. Line Deflection Schematic - A2

4. Frame Deflection Schematic - A3

5. Tuner IF Schematic - A4

6. Video IF And Sound IF Schematic - A5

7. Synchronization Schematic - A6

8. Control Schematic - A7

9. Audio Amplifier Schematic - A8

10. NICAM + 2CS + BTSC Schematic - A9

11. Audio/Video Source Switching Schematic - A10

Manual 7602

Model no.: 20LX200125 First Publish: 5-10-2001 Rev. Date: 10-16-2002 Print Date: 06/04/2007

12. Audio - BTSC Stereo Decoder Schematic - A11

13. Front I/O + Control, Headphone Schematic - A12

14. Rear I/O Cinch Schematic - A13

15. CRT Panel Schematic - B

16. Side AV + Headphone Panel Schematic - C

17. Main Chassis PCB (Top View)

18. Main Chassis PCB (Bottom View)

19. CRT Panel PCB (Top View)

20. CRT Panel PCB (Bottom View)

21. Side AV + Headphone Panel PCB (Top View)

REFER TO SAFETY GUIDELINES

SAFETY NOTICE

: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.

CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING

Philips Consumer Electronics

Technical Service Data

Service and Quality Service Publications Dept. One Philips Drive P.O. Box 14810 Knoxville, TN 37914

Manual 7602

Model no.: 20LX200125 First Publish: 5-10-2001 Rev. Date: 10-16-2002 Print Date: 06/04/2007

Mechanical Assembly

REFER TO SAFETY GUIDELINES

SAFETY NOTICE HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.

CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING

: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE

Rear Cover Removal

1. Remove all fixation screws of the rear cover.

2. Now pull the rear cover backward to remove it.

Service Position Main Panel

1. Disconnect the strain relief of the AC power cord.

2. Remove the main panel, by pushing the two center clips outward [1]. At the same time pull the panel away from the CRT [2].

3. Disconnect the degaussing coil by removing the cable from (red) connector 0201.

4. Move the panel somewhat to the left and flip it 90 degrees [3], with the components towards the CRT.

Side I/O Panel Removal

1. Remove the complete Side I/O assembly after unscrewing the 2 fixation screws.

2. Release the 2 fixation clamps and lift the board out of the bracket.

Rear Cover Mounting

Before you mount the rear cover, perform the following checks:

1. Check whether the AC power cord is mounted correctly in its guiding brackets.

2. Replace the strain relief of the AC power cord into the cabinet.

3. Check whether all cables are replaced in their original position.

Philips Consumer Electronics

Technical Service Data

Service and Quality Service Publications Dept. One Philips Drive P.O. Box 14810 Knoxville, TN 37914

Manual 7602

Model no.: 20LX200125 First Publish: 5-10-2001 Rev. Date: 10-16-2002 Print Date: 06/04/2007

Mechanical Diagrams

REFER TO SAFETY GUIDELINES

SAFETY NOTICE HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.

CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING

: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE

MAIN CABINET EXPLODED VIEW Page: 1 of 1

Philips Consumer Electronics

Technical Service Data

Service and Quality Service Publications Dept. One Philips Drive P.O. Box 14810 Knoxville, TN 37914

Manual 7602

Model no.: 20LX200125 First Publish: 5-10-2001 Rev. Date: 10-16-2002 Print Date: 06/04/2007

Troubleshooting

REFER TO SAFETY GUIDELINES

SAFETY NOTICE HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.

CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING

: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE

Service Modes, Error Codes And Fault Finding

Test Points

The chassis is equipped with test points printed on the circuit board assemblies. These test points refer to the functional blocks:

Test point Circuit Diagram

A1-A2-A3-.. Audio processing A8, A9 / A11 C1-C2-C3-.. Control A7 F1-F2-F3-.. Frame drive and output A3 I1-I2-I3-.. Tuner & IF A4 L1-L2-L3-.. Line drive and output A2 P1-P2-P3-.. Power supply A1 S1-S2-S3-.. Synchronization A6 V1-V2-V3-.. Video processing A5, B1

The numbering is in a logical sequence for diagnostics.

lways start diagnosing within a functional block in the sequence of the relevant test points for that block.

Perform measurements under the following conditions:

• Service Default Mode.

• Video: color bar signal.

• Audio: 3 kHz left, 1 kHz right.

Service Modes

Service Default Mode (SDM) and Service Alignment Mode (SAM) offer several features for the service technician, while the Customer Service Mode (CSM) is used for communication between dealer and customer. Note: Some L8 and M8 chassis sets use a software version that does not contain the Service Modes (see table). In this case, use the special Factory Mode Remote Control. This can be ordered by service code 4835 310 57511. Complete instructions are included. This remote control will place the TV in the Factory Mode and allow access to all adjustments that a normal Service Mode contains (including setting Option Bytes). Error codes will not be available. There is also the option of using ComPair, a hardware interface between a computer (see requirements) and the TV chassis. It offers the ability of structured trouble shooting, error code reading and software version readout for all L8 and M8 chassis. Requirements: To run ComPair on a computer (laptop or desktop) requires, as a minimum, a 486 processor, Windows 3.1 and a CD-ROM drive. A Pentium Processor and Windows 95/98 are also acceptable (see also

ComPair).

SW. cluster

1US0 L01UN0-x.y TDA9587 Stereo, All Servioce

Softwar name

UOC type Diversity Remark

1US0 L01UN0-x.y TDA9587 Stereo,

non-DBX, CC

1US1 L01US1-x.y TDA9587/

TDA9588

2US0 L01UM0-x.y TDA9587 Mono, CC All Service

2US1 L01UM1-x.y TDA9587 Mono, CC Without

3US0 L01US0-x.y TDA9588 Stereo,-DBXCCOnly

3US1 L01UN1-x.y TDA9587 Stereo,

Abbreviations in “Software Name”: U=USA, N=Stereo non-DBX, S=Stereo DBX, M=Mono

Stereo,-DBXCCOnly

non-DBX, CC

All Servioce Modes

Com-Pair (*)

Modes

CSM (*)

Con-Pair (*) Without CSM (*)

Service Default Mode (SDM)

Purpose

• To create a predefined setting to get the same measurement results as given in this manual.

• To override SW protections.

• To start the blinking LED procedure.

Specifications

• Tuning frequency: 61.25 MHz (channel 3).

• Color system: NTSC.

• All picture settings at 50 % (brightness, color contrast, hue).

• Bass, treble and balance at 50 %; volume at 25 %.

• All service-unfriendly modes (if present) are disabled, like:

− (sleep) timer,

− child/parental lock,

− blue mute,

− hotel/hospitality mode

− auto switch-off (when no 'IDENT' video signal is received for 15 minutes),

− skip / blank of non-favorite presets / channels,

− auto store of personal presets,

− auto user menu time-out.

How to enter SDM

• Use a standard customer RC-transmitter and key in the code 062596 directly followed by the MENU button, or

• Short wires 9631 and 9641 on the mono carrier and switch the set ON apply AC power. Then press the power

button (remove short after start-up). Caution: Entering SDM by shorten wires 9631 and 9641 will override the +8V-protection. Do this only for a short period. When doing this, the service-technician must know exactly what he is doing, as it could lead to damaging

fter entering SDM, the following screen is visible, with SDM at the upper right side for recognition.

How to navigate

• When you press the MENU button on the remote control, the set will switch between the SDM and the normal user

menu (with the SDM mode still active in the background). Return to the SDM screen with the OSD / STATUS button.

• When you press the OSD / STATUS button on the remote control, the menu will show or hide the error buffer.

This feature is available to prevent interference during waveform measurements.

• On the TV press and hold the 'VOLUME down' and press the 'CHANNEL down' for a few from SDM to SAM and

reverse.

How to exit

Switch the set to STANDBY by pressing the power button on the remote control transmitter (if you switch the set OFF by removing the AC power, the set will return in SDM when AC power is re-applied). The error buffer is cleared.

Service Alignment Mode (SAM)

Purpose

• To perform alignments.

• To change option settings.

• To display / clear the error code buffer.

Specifications

• Operation hours counter.

• Software version.

• Option settings.

• Error buffer reading and erasing.

• Software alignments.

How to enter

• Use a standard customer RC-transmitter and key in the code 062596 directly followed by the OSD / STATUS

button or

• Via ComPair.

The following screen is visible, with SAM at the upper right side for recognition.

1. LLLL This is the operation hours counter. It counts the normal operation hours, not the standby hours.

2. AAABCD-X.Y This is the software identification of the main micro controller

• A = the project name (L01).

• B = the region: E = Europe, A = Asia Pacific, U = NAF TA, L = LATAM.

• C = the software diversity: N = stereo non-DBX, S = stereo DBX, M = mono, D = DVD.

• D = the language cluster number.

• E = UOC diversity.

• X = the main software version number.

• Y = the sub software version number.

3. SAM Indication of the actual mode.

4. Errors buffer Five errors possible.

5. Option bytes Seven codes possible.

6. Clear Erase the contents of the error buffer. Select the CLEAR menu item and press the CURSOR RIGHT key. The content of the error buffer is cleared.

7. Options To set the Option Bytes. See chapter 8.3.1 for a detailed description.

8. AKB Disable (0) or enable (1) the 'black current loop' (AKB = Auto Kine Bias).

9. Tuner To align the Tuner. See chapter 8.3.2 for a detailed description.

10. White Tone To align the White Tone. See White tone for a detailed description.

11. Geometry To align the set geometry. See Geometry for a detailed description.

12. Audio No audio alignment is used for NTSC.

How to navigate

• In SAM, select menu items with the CURSOR UP/DOWN key on the remote control transmitter. The selected item

will be highlighted. When not all menu items fit on the screen, move the CURSOR UP/DOWN key to display the next / previous menu items.

• With the CURSOR LEFT/RIGHT keys, it is possible to:

− (De)activate the selected menu item.

− Change the value of the selected menu item.

− Activate the selected submenu.

• When you press the MENU button twice, the set will switch to the normal user menus (with the SAM mode still

active in the background). To return to the SAM menu press the OSD / STATUS button [ i+ ].

• When you press the MENU key in a submenu, you will return to the previous menu.

How to exit

Switch the set to STANDBY by pressing the power button on the remote control transmitter (if you switch the set OFF by removing the AC power, the set will return in SAM when AC power is re-applied). The error buffer is not cleared.

Customer Service Mode (CSM)

Purpose

The Customer Service Mode is (de-)activated by the customer upon request of the service technician during a telephone conversation, in order to identify the status of the set. This CSM is a read only mode, therefore modifications in this mode are not possible.

How to enter

The CSM will be turned on after pressing the MUTE key on the remote control transmitter and any of the control buttons on the TV for at least 4 seconds simultaneously. This activation only works if there is no menu on the screen.

fter switching ON the Customer Service Mode, the following screen will appear:

1. Software identification of the main micro controller (see Service Alignment Mode for an explanation).

2. Error code buffer (see for more details). Displays the last seven errors of the error code buffer.

3. In this line, the Option Bytes (OB) are visible. Each Option Byte is displayed as a decimal number between 0 and

255. The set may not work correctly when an incorrect option code is set. See Options for more information on the

option settings.

4. Indicates which color and sound system is installed for the selected pre-set.

5. Indicates if the set is not receiving an 'IDENT' signal on the selected source. It will display 'Not Tun ed'.

6. Indicates if the sleep timer is enabled.

7. Indicates if the V-chip feature is enabled.

8. Value indicates parameter levels at CSM entry.

CO = CONTRAST, CL = COLOR, BR = BRIGHTNESS, HU = HUE, SH = SHARPNESS

9. Value indicates parameter levels at CSM entry.

VL = VOLUME LEVEL, BL = BALANCE LEVEL, AVL LIM = AUTO VOLUME LEVEL LIMITER

10. Value indicates parameter levels at CSM entry.

DV = DELTA VOLUME, BS = BASS LEVEL, TR = TREBLE LEVEL

How to exit

You can turn the Customer Service Mode off:

• After you press 'any' key of the remote control transmitter with exception of the CHANNEL and VOLUME keys.

• After you switch-off the TV set with the AC power switch.

Problems And Solving Tips (Related To CSM)

Picture Problems

No colors / noise in picture

Check CSM line 4. Wrong color system installed. To change the setting:

1. Select the MANUAL STORE sub menu.

2. Select and change the SYSTEM setting until picture and sound are correct.

3. Select the STORE menu item.

Colors not correct / unstable picture

Check CSM line 4. Wrong color system installed. To change the setting:

1. Press the MENU button on the remote control.

2. Select the INSTALL sub menu.

3. Select the MANUAL STORE sub menu.

4. Select and change the SYSTEM setting until picture and sound are correct.

5. Select the STORE menu item.

TV switches off or changes channel without any user action

The TV set switches off after TV SWITCHING OFF was displayed.

uto standby switched the set off because:

• There was no 'ident' signal for more than 15 minutes or

• There was no remote control signal received or local key pressed for > 2 hours.

See Alignmentsfor a description of the options to enable / disable auto standby

Picture too dark or too bright

Increase / decrease the BRIGHTNESS and / or the CONTRAST value when:

• The picture improves after you have pressed the 'Smart Picture' button on the remote control.

• The picture improves after you have switched on the Customer Service Mode

The new 'Personal' preference value is automatically stored.

White line around picture elements and text

Decrease the SHARPNESS value when:

• The picture improves after you have pressed the 'Smart Picture' button on the remote control.

• The picture improves after you have switched on the Customer Service Mode

The new 'Personal' preference value is automatically stored.

Snowy picture

Check CSM line 5. If this line indicates 'Not Tuned', check the following:

• No or bad antenna signal. Connect a proper antenna signal.

• Antenna not connected. Connect the antenna.

• No channel / preset is stored at this program number. Go to the INSTALL menu and store a proper channel at this

program number.

• The tuner is faulty (in this case the CODES line will contain error number 10). Check the tuner and replace / repair

if necessary.

Snowy picture and/or unstable picture

• A scrambled or decoded signal is received.

Black and white picture

Increase the COLOR value when:

• The picture improves after you have pressed the 'Smart Picture' button on the remote control.

• The picture improves after you have switched on the Customer Service Mode

The new 'Personal' preference value is automatically stored.

Menu text not sharp enough

Decrease the CONTRAST value when:

• The picture improves after you have pressed the 'Smart Picture' button on the remote control.

• The picture improves after you have switched on the Customer Service Mode

The new 'Personal' preference value is automatically stored.

Sound Problems

No sound or sound too loud (after channel change / switching on)

Increase / decrease the VOLUME level when the volume is OK after you switched on the CSM. The new 'Personal' preference value is automatically sto r ed .

ComPair

Introduction

ComPair (Computer Aided Repair) is a service tool for Philips Consumer Electronics products. ComPair is a further development on the European DST (service remote control), which allows faster and more accurate diagnostics. Compare has three big advantages:

• ComPair helps you to quickly get an understanding on how to repair the chassis in a short time by guiding you

systematically through the repair procedures.

• ComPair allows very detailed diagnostics (on I

areas. You do not have to know anything about I

• ComPair speeds up the repair time since it can automatically communicate with the chassis (when the

2C level) and is therefore capable of accurately indicating problem

2 C commands yourself because ComPair takes care of this.

microprocessor is working) and all repair information is directly available. When ComPair is installed together with the SearchMan electronic manual of the defective chassis, schematics and PWBs are only a mouse click away.

Specifications

ComPair consists of a Windows based faultfinding program and an interface box between PC and the (defective) product. The ComPair interface box is connected to the PC via a serial or RS232 cable. In case of the L8/M8 chassis, the ComPair interface box and the TV communicate via a bi-directional service cable via the service connector (located on the Main panel, see Hardware alignments

The ComPair faultfinding program is able to determine the problem of the defective television. ComPair can gather diagnostic information in two ways:

1. Automatic (by communication with the television)

ComPair can automatically read out the contents of the entire error buffer. Diagnosis is done on I ComPair can access the I 2 C bus of the television. ComPair can send and receive I 2 C commands to the micro controller of the television. In this way, it is possible for ComPair to communicate (read and write) to devices on

2 C busses of the TV-set.

the I

2. Manually (by asking questions to you)

Automatic diagnosis is only possible if the micro controller of the television is working correctly and only to a certain extend. When this is not the case, ComPair will guide you through the faultfinding tree by asking you questions (e.g. Does the screen gives a picture? Click on the correct answer: YES / NO) and showing you examples (e.g. Measure test-point I7 and click on the correct oscillogram you see on the oscilloscope). You can answer by clicking on a link (e.g. text or a waveform picture) that will bring you to the next step in the faultfinding process.

By a combination of automatic diagnostics and an interactive question / answer procedure, ComPair will enable you to find most problems in a fast and effective way. Beside fault finding, ComPair provides some addition al features like:

• Up- or downloading of presets.

• Managing of preset lists.

• Emulation of the (European) Dealer Service Tool (DST).

• If both ComPair and SearchMan (Electronic Service Manual) are installed, all the schematics and the PWBs of the

set are available by clicking on the appropriate hyperlink.

suffix D).

2 C level.

Example: Measure the DC-voltage on capacitor C2568 (Schematic/Panel) at the Monocarrier. Click on the 'Panel' hyperlink to automatically show the PWB with a highlighted capacitor C2568. Click on the 'Schematic' hyperlink to automatically show the position of the highlighted capacitor.

How To Connect

1. First install the ComPair Browser software (see the Quick Reference Card for installation instructions).

2. Connect the RS232 interface cable between a free serial (COM) port of your PC and the PC connector (marked with 'PC') of the ComPair interface.

3. Connect the AC power adapter to the supply connector (marked with 'POWER 9V DC') on the compare interface.

4. Switch the ComPair interface OFF.

5. Switch the television set OFF, remove the AC power.

6. Connect the ComPair interface cable between the connector on the rear side of the ComPair interface (marked

2 C') and the ComPair connector on the mono carrier (see figure 8-1 suffix D).

with 'I

7. Plug the AC power adapter in the AC power outlet and switch on the interface. The green and red LEDs light up

together. The red LED extinguishes after approx. 1 second while the green LED remains lit.

8. Start the ComPair program and read the introduction chapter.

How To Order

ComPair order codes:

• Starter kit ComPair + SearchMan software + compare interface (excluding transformer): 4822 727 21629

• ComPair interface (excluding transformer): 4822 727 21631

• Starter kit ComPair software (registration version): 4822 727 21634

• Starter kit SearchMan software: 4822 727 21635

• ComPair CD (update): 4822 727 21637

• SearchMan CD (update): 4822 727 21638

• ComPair interface cable: 3122 785 90004

Error Codes

Introduction

The error code buffer contains all errors detected since the last time the buffer was erased. The buffer is written from left to right. When an error occurs that is not yet in the error code buffer, it is written at the left side and all other errors shift one position to the right. The error code buffer is cleared in the following cases:

• By activation of the CLEAR command in the SAM menu:

• When you exit SDM / SAM with the STANDBY command on the remote control (when leaving SDM / SAM, by

disconnecting the set from AC power, the error buffer is not reset).

• When you transmit the command DIAGNOSE-99-OK with ComPair.

• If the content of the error buffer has not changed for 50 hours, it resets automatically.

Examples: ERROR: 0 0 0 0 0: No errors detected. ERROR: 6 0 0 0 0: Error code 6 is the most recent and only detected error. ERROR: 9 6 0 0 0: Error code 6 was first detected and error code 9 is the most recent detected error. You can also make the contents of the error buffer visible via the blinking LED procedure (see The Blinking

ProcedureThis is especially useful when there is no picture.

LED

Error Codes

In case of non-intermittent faults, clear the error buffer before you begin the repair. These to ensure that old error codes are no longer present. If possible, check the entire contents of the error buffer. In some situations an error code is only the result of another error code and not the actual cause (e.g., a fault in the protection detection circuitry can also lead to a protection).

E Device Error description Symptom Check Diagram

0 - No Error - - 1 - X-Ray / over-voltage

protection

2 - High beam current CRT panel, 3340 B1, B2

- Horizontal Protection Set will hiccup until it goes to

3 TDA8359/

TDA9302

4 MSP34X5/

TDA9853

5 TDA95xx POR / +8V protection Set will hiccup until it goes to

I2C bus General I2C bus error

7 AN7522/3 Power down (over

8 - E/W protection (Large

9 M24C08

10 Tuner

11 TDA6107/8 Black current loop

12 M65669

Vertical Protection Set will hiccup until it goes to

MSP I2C identification error

current) protection

Screen)

NVM I2C identification error

Tuner I2C identification error

protection PIP I2C identification

error

Set will hiccup until it goes to protection mode

protection mode-Fly back line after 5 s in protection mode

protection mode-One hor. Line after 5 s in protection mode

Set turned on without sound output

protection mode after 8 s Set is in protection mode SDA/SCL, 1000,

Set will hiccup until it goes to protection mode

Geometry wrong or set in protection mode

Set will turn on but is unable to store data

Set will turn on but has no picture and sound

Fly back line after 5 s in protection mode

Picture in picture does not function

2407 & 7402 (L8),2465 & 7460 (M8)

+200V, LOT 5445, 7460-7463, 6467, hor. Defl. Coil

ViotlAux +13V, +50V (M8) 7471, vert. Defk, Coil

ViotlAux +5V, +8V,7831,3823/33, 7861,3865/66

3V3, +8V, 7200, 7560, 7480

7200, 7600/01, 3624/25

MainAux, 7901/02, 7561/62

ViotAux+11V, 3400, 3405/06, 7400

3V3, 7601/02, 3611, 3603/04

ViotlAux +5V, 1100, 7482

+200V, 7330, RGB amps, CRT

+5V, +8V, 7803, 7890/91

A2, A3

A9 or A11

A5-A7, A1, A2

A8, A1

A4, A2

B1, B2

The Blinking LED Procedure

Via this procedure you can make the contents of the error buffer visible via the front LED. This is especially useful when there is no picture.

When the SDM is entered, the LED will blink the contents of the error-buffer.

Error-codes ≥ 10 are shown as follows:

− a long blink of 750 ms (which is an indication of the decimal digit),

− a pause of 1.5 s,

− n short blinks (n = 1 - 9),

− when all the error-codes are displayed, the sequence finishes with a LED blink of 3 s,

− the sequence starts again.

Example of error buffer: 12 9 6 0 0

fter entering SDM:

− 1 long blink of 750 ms followed by a pause of 1.5 s,

− 2 short blinks followed by a pause of 3 s,

− 9 short blinks followed by a pause of 3 s,

− 6 short blinks followed by a pause of 3 s,

− 1 long blink of 3 s to finish the sequence,

− the sequence starts again.

Protections

If a fault situation is detected an error code will be generated and if necessary the set will be put in the protection mode. Blinking of the red LED at a frequency of 3 Hz indicates the protection mode. In some error cases the microprocessor does not put the set in the protection mode. The error codes of the error buffer can be read via the service menu (SAM), the blinking LED procedure or via ComPair. The DST diagnose functionality will force the set into the Service-standby, which is similar to the usual standby mode, however the microprocessor has to remain in normal operation completely. To get a quick diagnosis the chassis has three service modes implemented:

• The Customer Service Mode (CSM).

• The Service Default Mode (SDM). Start-up of the set in a predefined way.

• The Service Alignment Mode (SAM). Adjustment of the set via a menu and with the help of test patterns.

See for a detailed description Circuit description

Repair Tips

Below some failure symptoms are given, followed by a repair tip.

• Set is dead and makes hiccuping sound

'MainSupply' is available. Hiccupping stops when de-soldering L5561, meaning that problem is in the ' M ainSupply' line. No output voltages at LOT, no horizontal deflection. Reason: line transistor 7460 is defective.

• Set is dead, and makes no sound

Check power supply IC 7520. Result: voltage at pins 1, 3, 4, 5 and 6 are about 180 V and pin 8 is 0 V. The reason why the voltage on these pins is so high is because the output driver (pin 6) has an open load. That is why MOSFET 7521 is not able to switch. Reason: feedback resistor 3523 is defective. Caution: be careful measuring on the gate of 7521; circuitry is very high ohmic and can easily be damaged!

• Set is in hiccup mode and shuts down after 8 s.

Blinking LED (set in SDM mode) indicates error 5. As it is unlikely that ?P 'POR' and '+8V protection' happen at the same time, measure the '+8V'. If this voltage is missing, check transistor 7480.

• Set is non-stop in hiccup mode

Set is in over current mode; check the secondary sensing (opto coupler 7515) and the 'MainSupply' voltage. Signal 'Stdby_con' must be logic low under normal operation conditions and goes to high (3.3 V) under standb y and fault conditions.

• Set turns on, but without picture and sound

The screen shows snow, but OSD and other menus are okay. Blinking LED procedure indicates error 11, so problem is expected in the tuner (pos. 1000). Check presence of supply voltages. As 'Vlotaux+5V' at pin 5 and 7 are okay, 'VT_supply' at pin 9 is missing. Conclusion: resistor 3460 is defective.

• Set turns on, but with a half screen at the bottom.

Sound is okay

Blinking LED (set in SDM mode) indicates error 3. Check 'Vlotaux+11V' and '+50V'. If they are okay, problem is expected in the vertical amplifier IC 7471. Measure with a scope the waveform on pin 17 of the UOC. Measure also at pin 1 of IC 7471. If here the signal is missing, a defective resistor R3244 causes the problem.

Philips Consumer Electronics

Technical Service Data

Service and Quality Service Publications Dept. One Philips Drive P.O. Box 14810 Knoxville, TN 37914

Manual 7602

Model no.: 20LX200125 First Publish: 5-10-2001 Rev. Date: 10-16-2002 Print Date: 06/04/2007

General Information

REFER TO SAFETY GUIDELINES

SAFETY NOTICE HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.

CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING

: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE

GENERAL INFORMATION

L8 Chassis, Manual 7602 Note: For Service Information covering Commercial/Institutional

Models, refer to Manual 7602C.

Technical Specifications

udio ratings

1 W mono 2 x 1 W non-DBX stereo (LC stereo) 2 x 3 W DBX stereo (with SAP)

Reception

Tuning system : PLL Color systems : NTSC Sound systems : FM-mono

: BTSC non-DBX

BTSC DBX A/V connections : NTSC M Channel selections : 181 channels, full cable IF frequency : 45.75 MHz Aerial input : 75 Ω, Coax

Miscellaneous

AC voltage : 90 - 140 V (±10 %) AC frequency : 60 Hz (±5 %) Ambient temperature : + 5 to + 45 deg. C Maximum humidity : 90 % Power consumption : 36 W (14")

100 W (32") Standby Power consumption : < 3 W

Connections

Front Or Top Control, Front Or Side Connections

udio / Video In

1 - Video 1 Vpp / 75 Ω 2 - Audio L (0.2 Vrms / 10 kΩ) 3 - Audio R (0.2 Vrms / 10 kΩ) 4 - Headphone

(3.5 mm) 8 - 600 Ω/ 4 mW

Rear Connections

Monitor Out

1 - Video 1 Vpp / 75 Ω 2 - Audio L (0.5 Vrms / 1 kΩ) 3 - Audio R (0.5 Vrms / 1 kΩ)

YUV In

1 - Y 0.7 Vpp / 75 Ω 2 - U 0.7 Vpp / 75 Ω 3 - V 0.7 Vpp / 75 Ω

V1 In

4 - Video 1 Vpp / 75 Ω 5 - Audio L (0.5 Vrms / 10 kΩ) 6 - Audio R (0.5 Vrms / 10 kΩ)

V2 In

1 - Video 1 Vpp / 75 Ω 2 - Audio L (0.5 Vrms / 10 kΩ) 3 - Audio R (0.5 Vrms / 10 kΩ)

V2 In (SVHS)

1 - gnd 2 - gnd 3 - Y 1 Vpp / 75 Ω 4 - C 0.3 Vpp / 75 Ω

Safety Instructions For Repairs

Safety regulations require that during a repair:

• Due to the 'hot' parts of this chassis, the set must be connected to the AC power via an isolation transformer.

• Safety components, indicated by the symbol , should be replaced by components identical to the original

ones.

• When replacing the CRT, safety goggles must be worn.

Safety regulations require that after a repair, the set must be returned in its original condition. Pay particular attention to the following points:

• General repair instruction: as a strict precaution, we advise you to re-solder the solder connections through which

the horizontal deflection current is flowing, in particular:

− all pins of the line output transfo rmer (LOT)

− fly-back capacitor(s)

− S-correction capacitor(s)

− line output transistor

− pins of the connector with wires to the deflection coil

− other components through which the deflection current flows.

Note: This re-soldering is advised to prevent bad connections due to metal fatigue in solder connections and is therefore only necessary for television sets more than two years old.

• Route the wire trees and EHT cable correctly and secure them with the mounted cable clamps.

• Check the insulation of the AC power cord for external damage.

• Check the strain relief of the AC power cord for proper function, to prevent the cord from touching the CRT, hot

components, or heat sinks.

• Check the electrical DC resistance between the AC plug and the secondary side (only for sets that have an

isolated power supply). Do this as follows:

1. Unplug the AC power cord and connect a wire between the two pins of the AC plug.

2. Turn on the main power switch (keep the AC power cord unplugged!).

3. Measure the resistance value between the pins of the AC plug and the metal shielding of the tuner or the aerial connection of the set. The reading should be between 4.5 MΩ and 12 MΩ.

4. Switch the TV OFF and remove the wire between the two pins of the AC plug.

• Check the cabinet for defects, to prevent the possibility of the customer touching any internal parts.

Maintenance Instructions

It is recommended to have a maintenance inspection carried out by qualified service personnel. The interval depends on the usage conditions:

• When the set is used under normal circumstances, for example in a living room, the recommended interval is three to five years.

• When the set is used in an environment with higher dust, grease or moisture levels, for example in a kitchen, the recommended interval is one year.

• The maintenance inspection includes the following actions:

1. Perform the 'general repair instruction' noted above.

2. Clean the power supply and deflection circuitry on the chassis.

3. Clean the picture tube panel and the neck of the picture tube.

Warnings

• In order to prevent damage to ICs and transistors, avoid all high voltage flashovers. In order to prevent damage to the picture tube, use the method shown in figure below, to discharge the picture tube. Use a high voltage probe and a multi-meter (position VDC). Discharge until the meter reading is 0 V (after approx. 30 s).

• All ICs and many other semiconductors are susceptible to electrostatic discharges (ESD). Careless handling during repair can reduce life drastically. When repairing, make sure that you are connected with the same potential as the mass of the set by a wristband with resistance. Keep components and tools also at this potential. Available ESD protection equipment:

− Complete kit ESD3 (small tabl emat, wristband, connection box, extension cable, and ground cable) 4822 310

10671.

− Wristband tester 4822 344 13999.

• Together with the deflection unit and any multi-pole unit, flat square picture tubes form an integrated unit. The

deflection and the multi-pole units are set optimally at the factory. Adjustment of this unit during repair is therefore not recommended.

• Be careful during measurements in the high voltage section and on the picture tube.

• Never replace modules or other components while the unit is switched ON.

• When you align the set, use plastic rather than metal tools. This will prevent any short circuits and the danger of a

circuit becoming unstable.

Notes

• Measure the voltages and waveforms with regard to the chassis (= tuner) ground ( ), or hot ground ( ), depending on the area of circuitry being tested.

• The voltages and waveforms shown in the diagrams are indicative. Measure them in the Service Default Mode with a color bar signal and stereo sound (L: 3 kHz, R: 1 kHz unless stated otherwise) and picture carrier at 475.25 MHz (PAL) or 61.25 MHz (NTSC, channel 3).

• Where necessary, measure the waveforms and voltages with ( voltages in the power supply section both in normal operation ( ) and in standby ( ). These valu es are indicated

) and without ( ) aerial signal. Measure the

by means of the appropriate symbols.

• The picture tube panel has printed spark gaps. Each spark gap is connected between an electrode of the picture tube and the Aquadag coating.

• The semiconductors indicated in the circuit diagram and in the parts lists are completely interchangeable per position with the semiconductors in the unit, irrespective of the type indication on these semiconductors.

Abbreviation list

2CS 2 Carrier (or Channel) Stereo ACI Automatic Channel Installation: algorithm that installs TV sets directly from cable network

by means of a predefined TXT page ADC Analogue to Digital Converter AFC Automatic Frequency Control: control signal used to tune to the correct frequency AFT Automatic Fine Tuning AGC Automatic Gain Control: algorithm that controls the video input of the featurebox AM Amplitude Modulation AP Asia Pacific AR Aspect Ratio: 4 by 3 or 16 by 9 ATS Automatic Tuning System AV External Audio Video AVL Automatic Volume Level BC-PROT Beam Current Protection BCL Beam Current Limitation B/G Monochrome TV system. Sound carrier distance is 5.5 MHz BLCINFORMATION Black current informationrmation BTSC Broadcast Television Standard Committee. Multiplex FM stereo sound system,

originating from the USA and used e.g. in LATAM and AP-NTSC countries B-TXT Blue teletext CC Closed Caption ComPair Computer aided rePair CRT Cathode Ray Tube or picture tube CSM Customer Service Mode CTI Colour Transient Improvement: manipulates steepness of chroma transients CVBS Composite Video Blanking and Synchronisation DAC Digital to Analogue Converter DBE Dynamic Bass Enhancement: extra low frequency amplification DBX Dynamic Bass Expander D/K Monochrome TV system. Sound carrier distance is 6.5 MHz DFU Direction For Use: description for the end user DNR Dynamic Noise Reduction DSP Digital Signal Processing DST Dealer Service Tool: special remote control designed for dealers to enter e.g. service

mode DVD Digital Versatile Disc EEPROM Electrically Erasable and Programmable Read Only Memory EHT Extra High Tension EHT-

INFORMATION Extra High Tensioninformationrmation EU Europe EW East West, related to horizontal deflection of the set EXT External (source), entering the set via SCART or Cinch FBL Fast Blanking: DC signal accompanying RGB signals FILAMENT Filament of CRT FLASH Flash memory FM Field Memory FM Frequency Modulation HA Horizontal Acquisition: horizontal sync pulse coming out of the HIP HFB Horizontal Flyback Pulse: horizontal sync pulse from large signal deflection HP Headphone Hue Colour phase control for NTSC (not the same as 'Tint') I Monochrome TV system. Sound carrier distance is 6.0 MHz I2C Integrated IC bus IF Intermediate Frequency IIC Integrated IC bus Interlaced Scan mode where two fields are used to form one frame. Each field contains half the

number of the total amount of lines. The fields are written in "pairs", causing line flicker. ITV Institutional TV LATAM Latin America LED Light Emitting Diode L/L' Monochrome TV system. Sound carrier distance is 6.5 MHz. L' is Band I, L is all bands

except for Band I LNA Low Noise Amplifier LS Large Screen LS Loudspeaker LSP Large signal panel M/N Monochrome TV system. Sound carrier distance is 4.5 MHz MSP Multistandard Sound Processor: ITT sound decoder MUTE Mute-Line NC Not Connected NICAM Near Instantaneous Compounded Audio Multiplexing. This is a digital sound system,

mainly used in Europe. NTSC National Television Standard Committee. Colour system mainly used in North America

and Japan. Colour carrier NTSC M/N = 3.579545 MHz, NTSC 4.43 = 4.433619 MHz (this

is a VCR norm, it is not transmitted off-air) NVM Non Volatile Memory: IC containing TV related data e.g. alignments OB Option Byte OC Open Circuit OSD On Screen Display PAL Phase Alternating Line. Colour system mainly used in West Europe (colour carrier =

4.433619 MHz) and South America (colour carrier PAL M = 3.575612 MHz and PAL N =

3.582056 MHz) PCB Printed Circuit board PIP Picture In Picture PLL Phase Locked Loop. Used for e.g. FST tuning systems. The customer can give directly

the desired frequency POR Power-On Reset Progressive Scan Scan mode where all scan lines are displayed in one frame at the same time, creating a

double vertical resolution. PTP Picture Tube Panel (or CRT-panel) RAM Random Access Memory RC Remote Control handset RC5 Remote Control system 5, signal from the remote control receiver RGB Red Green Blue ROM Read Only Memory SAM Service Alignment Mode SAP Second Audio Program SC Sandcastle: pulse deri ved from sync signals S/C Short Circuit SCAVEM Scan Velocity Modulation SCL Serial Clock SDA Serial Data SDM Service Default Mode SECAM SEequence Couleur Avec Memoire. Colour system mainly used in France and East

Europe. Colour carriers = 4.406250 MHz and 4.250000 MHz SIF Sound Intermediate Frequency SS Small Screen STBY Standby SVHS Super Video Home System SW Software THD Total Harmonic Distortio n TXT Teletext µP Microprocessor UOC Ultimate One Chip VA Vertical Acquisition VBAT Main supply voltage for the deflection stage (mostly 141 V) V-chip Violence Chip VCR Video Cassette Recorder WYSIWYR What You See Is What You Record: record selection that follows main picture and sound XTAL Quartz crystal YC Luminance (Y) and Chrominance (C) signal

Schematic notes

Items marked with a *, but not mentioned in the diversity table have no diversity in this product.

Schematic notes

Items marked with a *, but not mentioned in the diversity table have no diversity in this product.

$ K +

Schematic notes

Items marked with a *, but not mentioned in the diversity table have no diversity in this product.

Schematic notes

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