Philips 21CE1250 Manuel de service télécharger pdf (Page 2)

the page header when subtitles are being received. The new version (MAB8461P/W196) is available from service under code no. 4822

209 62479. In cases of specific complaint the new version may be fitted as a drop-in replacement.

13. Control micro processors. A production change has been introduced adding a shield to the control micro processor to prevent the

processor being influenced by external fields. In future replacements will be supplied as a kit comprising the processor, shield and

fitting instruction. The shield will also be available separately.

Old mask no. Code no. CP90/110 TMP47C432P 8187 -

8188 4822 209 72038 8189 4822 209 73665

New mask no. Kit code no.

8188 4822 310 31849

8189 4822 310 31851

14. Safety test after repair.

Note: Due to defective components in an appliance (capacitors etc.) parts of the appliance can become charged. This cannot be

established when an appliance is tested on an isoformer. For safety reasons the appliance must also be connected to a non separated

socket and then checked that touchable parts (aerial, external connections etc.) are not charged.

15. Multiple defects of the BUT11AF.

Fault 1: To remedy this it is advisable to replace diode 6674 with a BYD33J, code number 4822 130 42606.

16. Picture tube A51EAM32X16

Note: Picture tube A51EAM32X16 (9301 206 10142) is used for 21" appliances from production code PM04 or BA04 onwards. Fixing

bracket for demagnetization coil must be used with this picture tube (4822 404 30945).

Introduction of picture tube brings along changed to tube base PCB. Part no. picture tube base PCB 4822 116 23121. On this tube base

PCB R3409, R3429 and R3449 have changed to 620R (4822 116 52227).

Picture tube A51EAM32X16 : 9301 206 10142

17. Code numbers for locking HT- and focus cable. Note: :Locking for HT-cable (red) 4822 417 50225

:Locking for focus cabel (blue) 4822 417 50226

18. Service note. It is worthwhile replacing the flyback tuning capacitor C2619 (1kV/1.5nF) with the 2kV type whenever one of these

sets is serviced. Part no.: 4822 122 32501.

19. uP + screening. Note: TMP47C432AP with screening:

-8188: 4822 310 31849 replaces 8187, standard TXT (provided decoder is present).

-8189: 4822 310 31851, TOP/FLOF TXT (Fastext) (provided decoder is present).

Connect screen to bridging wire 9732.

20. Testing the power supply.

Note 1: Remove connector M6 and connect a 60W light bulb across C2696 and monitor the DC voltage. Apply Mains via a variac, the

bulb should light when the DC voltage is about 70V and it should stabilise at 95V. If the voltage does not stabilise then check the

components around the optocoupler CNX62 and set the HT control to 95V.

21. When checking for dry joints. Look in the IF/sync can, especially around the TDA2579 chip.

DEFLECT

1. The line transistor BU11AF always breaks down after a few seconds. Fault 1: C2610 has leaked (8.2nF/2KV).

2. Top of raster folds together. Fault 1: Replace C2572 (1.5µF).

3. Horizontal deflection is defective, only a line in the picture. Fault 1: C2610 is open circuit and should be replaced.

4. No synchronization. Fault 1: Replace U 1040 (4822 212 22739).

5. No vertical deflection.

Fault 1: Replace R 3623 (8.2 Ohm) (4822 111 30506). Replace TS7571 and TS7573 (BD939F; 4822 130 42681).

6. Field collapse. Fault 1: Check voltage on R3571 (18K 2 watt just to the front of the frame transistors - the resistor is also used by the

RGB o/p stage and is in the line output 163V stage). If no voltage fuseable R3623 8R is O/C. Find R3623 right beside the LOPT from

pin 1.

Fault 2: Check the print by R3275. Fault 3: Check R3581 for break to pin 1 of sync/IF panel.

7. Only half inch field scan in center of screen. Fault 1: Check r 3582 3.3ohm o/c.

8. Field scan reduced to half an inch in the centre of the screen.

Fault 1: Scan current chassis return resistor R3582 (3.3ohm) was o/c.

9. Partial frame collapse. Fault 1: R3623

10. Partial fram collapse, very bright screen. Fault 1: R3623. This is an 8R2 fuse feeding 165 volts to the frame. Find it beside and to

the left of the LOPT next to a Wickman fuse. I suspect it may fail due to drys on the frame transistors.

11. Horizontal BUT is defective. The new one blows again straight away. Fault 1: Check C 2610, loss of capacity.

12. Field collapse with a small amount of scan below it, no 95V supply to the field output stage.

Fault 1: Check for crack in print by R3275.

13. Low field. Fault 1: Check R3582 (3.3ohm).

14. Frame collapse. Fault 1: R3623 (8.2ohm) is O/C.

15. Rolling. Fault 1: Check TDA2579 on IF/sync panel.

16. Field bounce. Fault 1: Replace timebase generator chip TDA2579.

17. Poor line linearity at centre of screen. Fault 1: Check D6609 and D6610 in EW modulator circuit.

18. Line folding in middle, when cold. OK after 2 mins. Possibly destroys line output transistor every few days.

Fault 1: Check C2523 (6.8nF/63V) at 12V rail to line drive

19. . Field jitter and line pulling. Fault 1: Check C2075 (10uF).

20. Very low 1/2" field scan. Fault 1: Check R3582 (3R3).

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Philips 21CE1250 Manuel de service Page 2

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