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If the fuse really blows absolutely instantly then this points to a short somewhere quite near the AC power input. The most common places would be:
1. Transient voltage suppression = metal oxide varistor
2. Degauss PTC
3 Diodes in main bridge rectifier
4 Main filter capacitor
5. Power supply regulator (Power supply chopper transistor )
In order to be able to eliminate these one by one need to do some small steps.
First read the safety guidelines: Safety Guidelines for High Voltage and/or Line Powered Equipment
0. Start by disconnect the main plug from the power lines
1. Replace main fuse with a 230Vac/60W light bulb. (see picture #1)
2. Disconnect jumpers JS801/JS802 (see picture #2)
3. Reconnect main plug to the power lines
4. Close main switch
5. If light bulb will be permanently on, problems may be related to the MOV (see picture #3) or PTC (see picture #4)
6. If light bulb shortly flash, then need to go one step ahead.
7. Disconnect main plug from power lines
8. Reconnect jumpers JS801/JS802
9. Disconnect jumper JS826 (see picture #5)
10. Reconnect power lines/ Close main switch
11. Light bulb permanently ON, problems may be related to the bridge rectifier (see picture #6)
12. Leave some time in between to discharge the main capacitor before start measuring in the circuit
13. Other problems may be related to capacitors: C817/C807/C806/C809/C803 C824
14. Light bulb pulse shortly ON and then OFF problems to the IC801 (see picture #10)
15. Leave some time in between to discharge the main capacitor before start measuring in the circuit
16. Measure resistance between pin 1 and pin 3 of the integrated circuit, low resistance = Replace IC801
17. Check/Replace R809/R835
18. Replace C811 (see picture #9)
19. Need to test power supply. Disconnect tv set from power lines. Replace light bulb with standard fuse F801
20. Disconnect Q551 collector from the circuit
21. Reconnect the test light bulb 230Vac/60W from TPA12 to the GND.(+ capacitor C865)
22. Reconnect tv to the power lines. Light bulb need to be permanently ON (medium light as not powered at nominal voltage).
23. Test to obtain 140V on C865
24. Disconnect tv from power lines
25. Leave some time to discharge capacitors
26. Test /replace Q551
27. If Q551 OK, problems may be related to the high voltage transformer/horizontal deflection circuits/additional components related to
28. Replace also capacitor C865 /68-100uF/160V
@mister_rf
Hi !
thanks for taking the trouble to post a lengthy analysis
Sure enough the power supply main bridge rectifier D802 was shorted so i replaced it and now the set is running fine
A circuit diagram is very helpful in the sense that it gives you an overall picture of all components and wiring
best regards !
@mister_rf
@baraka42
Hi !
do you happen to know the service mode code for this Panasonic color tv?
I would like to adjust the picture height and width etc
thanks !
regards
@mister_rf
@baraka42
Hi !
do you happen to know the service mode code for this Panasonic color tv?
I would like to adjust the picture height and width etc
thanks !
regards
hai i am baburajan
i will tell u a service mode . but dont know that it wil help u
'first u set volume to zero then timer to "30" then press vol- & display button on remote at a same time
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