Philips 21CE1250 Manuel de service télécharger pdf (Page 3)

COLOUR

1. Optimal values are not stored any more. After switching on only picture without colour, no sound. With the remote control the

saturation and volumes can be adjusted.

Fault 1: Select program site 38 and press "Store" and program "+" at the same time (switch off hotel mode). Perhaps processor

TMP47C432 is defective. Also solder in the screening plate.

2. No colour when replacing IC7261 TDA3565/N4 by version /N6. Fault 1: Restriction: Non scart

Add a ceramic plate capacitor of 56pF (4822 122 31772) in series with 1261. Connect the capacitor between 1261 and earth.

Fault 2: Replace 56pF by a trimmer of 22pF (4822 125 50045) and adjust. In some sets combination of 3265 and 3266 is present as a

10K potmeter. Check adjustment of that potmeter, approx 6.8V on slider is normal.

3. Colour spots in flat square picture tubes. Fault 1: Colour spots may have several causes: local dooming, defective picture tube,

malfunctioning of demagnetization or presence of magnetic fields. Too often local dooming is said to cause the problem. Check other

possible causes with a pattern generator.

4. No colour. Fault 1: Check decoupling capacitor C2278 (22nF) for leaks.

PICTURE

1. The picture shows lines. Fault 1 R3623 is defective.

2. The picture has been shifted and the width control does not work. Fault 1 C2260 is defective.

3. The picture is too small and contrast cannot be controlled.

Fault 1 There is no contact on base _7 of the line transformer capacitor 2405 (33µF/100V) has a short circuit.

4. Picture rolling. Fault 1 IF/sync panel (TDA2579).

5. The picture is wobbly. Fault 1 Change the sops transformer (foil type).

6. Sometimes the picture jitters. Fault 1 Stops-transformer in the power supply unit must be checked.

7. No picture and display, the voltage is present. Fault 1 Replace fuse 3623 (630mA).

8. In TXT the picture is black and sometimes coloured lines. TV picture is ok.

Fault 1: Change SAA5241 on the TXT module.

9. No picture. Fault 1: T7619 (BuT11D), TR5620 (line output).

Fault 2: Failure of the first anode supply due to an internal defect in the line output transformer.

Fault 3: No sync pulse on point 3 of the IF/sync unit. IC7038 in the IF/Sync unit is defective (TDA2541).

Fault 4: [Tr7619 continuously fails]. Check C2619 (1nF) and C2610.

10. No display, no functions, snow in picture. Fault 1: Fuse 630mA by the line transformer is defective, position 3623.

11. Vertical line (V-lock). Fault 1: IC TDA2579 on the synchronisation module is defective.

12. No picture, no sound. Power supply is ok.

Fault 1: Check if there is a signal on Pin 18 of the MF-module, and no longer on Pin 16. TDA2541 in MF-module is defective

13. Sometimes no sound, no picture. Fault 1: Voltage +95 V present. Replace U 1040 (4822 212 22739).

14. No picture, no sound. Fault 1: Voltage +95V present. Replace S5620 (line transformer; 4822 140 10306).

Fault 2: Voltage +95V present. Replace U1040 (4822 212 22739). Fault 3: Is high voltage present ? Check +95V. Also check +22V.

Replace fuse 1690 and if necessary D6690, IC7101, C 2101, C2102 and C2691.

:4822 253 10064 T400mA (fuse 1690) :4822 209 70872 TDA8190 (D6690)

Fault 4: Check +12V. If it is missing check the oscillogram on point 2 of T 5620. Check and replace R3638, R3639 and D6638.

:4822 111 30448 1ohm (R3638 and R3639) :4822 130 42489 BYD33G (D6638)

Fault 5: No 11.5V supply at cathode of thyristor 6726. Check D6733 (BAV19) and replace if necessary.

Fault 6: Power supply is ok. Check if there is a signal on pin 18 of the MF-module, and no longer on pin 16. TDA2541 in MF-module is

defective (part no 132180). Fault 7: Replace fuse 3623 (630mA).

Fault 8: [Power supply ok and tube heaters glow, microcontroller chip's 6V supply missing]. Check D6733 (BAV19) for open circuit.

Fault 9: Check line output transistor T7677 for dry joints.

Fault 10: Check R3623 (8R2) for H/R, fuse 1640 stays ok but D6667 (1N4148) goes O/C. This gives roughly half of 95V and 163V and

the set is in standby mode.

15. No picture, sound OK. Fault 1: Replace U 1040 (4822 212 22739).

Fault 2: No synchronisation pulse on pin 3 of the IF/Sync.-Unit. IC7038 on the IF/Sync. Unit is defective (TDA2541).

Fault 3: The supply of the first anode has collapsed due to a defect of the line output transformer.

Fault 4: Check T7619 (BUT11D), TR5620 (line output).

Fault 5: Check sandcastle-pulse. If it is ok, replace TDA2579 in the IF.

16. Brightness level change in A/V mode. Fault 1: It is possible that some video equipment will provide a CVBS signal slightly in

excess of the 1 volt peak-to-peak level required. This will cause a change in brightness level when switching between external A/V

mode and the RF signal which some viewers may find objectionable. The phenomena can be reduced by attenuating the CVBS input as

follows : Replace link 9506 with an 18R resistor Change R3525 from 75R to 56R.

Note: This change will not be introduced into production but may be applied in cases of specific complaint only.

17. White screen with flyback lines. Fault 1: Check IC (TDA3561).

18. Patterning on RF. After checking around the power supply it was found that +19V rail was incorrect and replacing C2691 (330uF)

rectified the fault.

19. Picture is very dark. Fault 1: Check if C2495 (33nF) is defective and upsetting the beam limiter action. A clue could be the low

contrast control voltage at the colour decoder chip.

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Philips 21CE1250 Manuel de service Page 3

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