PHILIPS L9.2A AA Service Manual

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270599

Colour Television Chassis

L9.2A

Contents Page

1. Technical Specifications 2

2. Safety- and maintenance instructions, 3 warnings and notes. 4

3. Directions for use 5

4. Mechanical instructions 14

5. Service modes, faultfinding and repair tips 15

6. Faultfinding trees 21 Supply voltage diagram 25 Blockdiagram 26 Testpointsoverview and oscillograms 27

Electrical diagram’s en PWB’s Diagram PWB

7. Power supply (Diagram A1) 28 34/37 Diversity table A1 29 Horizontal deflection (Diagram A2) 30 34/37 Vertical deflection (Diagram A3) 31 34/37 Synchronisation (Diagram A4) 31 34/37 Tuner en video IF (TDA 8844) (Diagram A5) 32 34/37 Diversity table A5 33 Video processing (Diagram A6) 38 34/37 Control (Diagram A7) 39 34/37 Front control (Diagram A8) 40 34/37 Smart sound & mono amplifier (Diagram A10) 41 34/37 Front cinch and headphone (Diagram A11) 42 34/37 Rear IO Cinches (Diagram A12) 43 34/37 CRT Panel (Diagram B) 44 45 BTSC decoder (Diagram C1) 46 48 BTSC Audio amplifier (Diagram C2) 47 48 ITT Audio decodering (Diagram D1) 49 45 ITT Audio amplifier (Diagram D2) 50 45 Side AV panel (Diagram E) 51 51

8. Alignments 53

9. Circuit description new circuits and 56 list of abbreviations 61

10. Spareparts list 64

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Copyright reserved 1999 Philips Consumer Electronics B.V. Eindhoven, The Netherlands. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise without the prior permission of Philips.

Published by JvR 9965 Service PaCE Printed in the Netherlands Subject to modification 5 4822 727 21705

GB 2 L9.2A1.

Technical Specifications

1. Technical Specifications

1.1 Specifications

Mains voltage : 150V - 276Vac; Mains frequency : 50 - 60Hz Maximum power consumption :

• 14" : 40W +/- 10%

• 20" : 56W +/- 10%

• 21" : 58W +/- 10% Standby power consumption : 10W +/- 10% Max. Antenne-input :

1.2 Specification of the terminal sockets

Red

Off air : 100dBV On air : 90dBV Audio output :

• Stereo : 2 * 3W; 2 * 1W

• Mono : 2 * 2W; 4W; 3W; 2W; 1W

Tuners :

• UV 1316/AI-2 (PAL)

• UV 1316/AIU-2 (PAL)

• UV 1356C/AI (PAL)

ChannelVolume

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080299

1.3 Specification of the terminal sockets

1.3.1 Inputs (AV1, AV2 and Side AV)

- Cinch CVBS (yellow) (1Vpp +/- 3dB 75Ω)

- Cinch Audio R (red) (0.2-2VRMS 10kΩ)

- Cinch Audio L (white) (0.2-2VRMS 10kΩ)

1.3.2 Outputs (MONITOR out)

- Cinch CVBS (yellow) (1Vpp +/- 3dB 75Ω)

- Cinch Audio R (red) (0.5VRMS < 1kΩ)

- Cinch Audio L (white) (0.5VRMS < 1kΩ)

1.3.3 Headphone

- Jack 8-600 (4mW)

1.3.4 SVHS

S-Video

q q q

IN OUTIN

Video

L Audio R

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1 - Ground 2 - Ground 3 - Y (1Vpp +/- 3dB 75Ω) 4 - C (0.3Vpp +/- 3dB 75Ω)

v v p p

Safety instructions, maintenance instruction, warnings and Notes

1.4 PCB location drawing

GB 3L9.2A 2.

D1 D2

C1 C2

SIDE AV PANEL

ITT AUDIO DECODING ITT AUDIO AMPLIFIER

BTSC DECODER

AUDIO AMPLIFIER

AUDIO PANEL

MAIN

CRT PANEL

POWER SUPPLY LINE DEFLECTION FRAME DEFLECTION SYNCHRONISATION TUNER VIDEO IF VIDEO PROCESSING CONTROL FRONT CONTROL SMART SOUND +

MONO SOUND AMPLIFIER FRONT CINCH +

HEADPHONE REAR I/O CINCHES

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A1 A2 A3 A4 A5 A6 A7

A10

A11

A12

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2. Safety instructions, maintenance instruction, warnings and Notes

2.1 Safety instructions for repairs h?????????

h?????????

h?????????h?????????

1. Safety regulations require that during a repair: – The set should be connected to the mains via an

isolating transformer;

– Safety components, indicated by the symbol h,

should be replaced by components identical to the original ones;

– When replacing the CRT, safety goggles must be

worn.

2. Safety regulations require that after a repair the set must be returned in its original condition. In particular attention should be paid to the following points. – As a strict precaution, we advise you to resolder the

solder joints through which the horizontal deflection current is flowing, in particular ('general repair instruction'):

• All pins of the line output transformer (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 resoldering is advised to prevent bad connections due to metal fatigue in solder joints and is therefore only necessary for television sets older than 2 years.

– The wire trees and EHT cable should be routed

correctly and fixed with the mounted cable clamps.

– T he insulation of the mains lead should be checked for

external damage.

2.2 Maintenance instruction

– The mains lead strain relief should be checked for its

function in order to avoid touching the CRT, hot components or heat sinks.

– The electrical DC resistance between the mains plug

and the secondary side should be checked (only for sets which have a mains isolated power supply). This check can be done as follows:

• Unplug the mains cord and connect a wire between the two pins of the mains plug;

• Set the mains switch to the "on" position (keep the mains cord unplugged!);

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

Ω

• Switch off the TV and remove the wire between the two pins of the mains plug.

– The cabinet should be checked for defects to avoid

touching of any inner parts by the customer.

It is recommended to have a maintenance inspection carried out by a qualified service employee. 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 3 to 5 years.

– When the set is used in circumstances with higher dust,

grease or moisture levels, for example in a kitchen, the recommended interval is 1 year.

– The maintenance inspection contains the following actions:

• Execute the above mentioned 'general repair instruction'.

GB 4 L9.2A2.

• Clean the power supply and deflection circuitry on the

• Clean the picture tube panel and the neck of the picture

Safety instructions, maintenance instruction, warnings and Notes

chassis.

tube.

2.3 Warnings

1. ESD

2. All ICs and many other semiconductors are susceptible to

3. Available ESD protection equipment:

4. In order to prevent damage to ICs and transistors, all high-

5. Together with the deflection unit and any multipole unit, the

6. Be careful during measurements in the high-voltage

7. Never replace modules or other components while the unit

8. When making settings, use plastic rather than metal tools.

9. Wear safety goggles during replacement of the picture

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 same potential.

– Complete kit ESD3 (small table mat, Wristband,

Connection box, Extension cable and Earth cable) 4822 310 10671

– Wristband tester 4822 344 13999

voltage flashovers must be avoided. In order to prevent damage to the picture tube, the method shown in Fig. 2.1 should be used to discharge the picture tube. Use a highvoltage probe and a multimeter (position DC-V). Discharge until the meter reading is 0V (after approx. 30s).

flat square picture tubes used form an integrated unit. The deflection and the multipole units are set optimally at the factory. Adjustment of this unit during repair is therefore not recommended.

section and on the picture tube.

is switched on.

This will prevent any short circuits and the danger of a circuit becoming unstable.

tube.

CL 26532098/042

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Figure 2-1

2.4 Notes

The direct voltages and oscillograms should be measured with regard to the tuner earth (v), or hot earth (u) as this is called. The direct voltages and oscillograms shown in the diagrams are indicative and should be measured in the Service Default Mode (see chapter 8) with a colour bar signal and stereo sound (L:3 kHz, R:1 kHz unless stated otherwise) and picture carrier at 475.25 MHz. Where necessary, the oscillograms and direct voltages are measured with (D) and without aerial signal (E). Voltages in the power supply section are measured both for normal operation (G) and in standby (F). These values are indicated by means of the appropriate symbols. The picture tube PWB 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.

Directions for use

3. Directions for use

GB 5L9.2A 3.

GB 6 L9.2A3.

Directions for use

GB 7L9.2A 3.

GB 8 L9.2A3.

Directions for use

GB 9L9.2A 3.

GB 10 L9.2A3.

Directions for use

GB 11L9.2A 3.

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