Troubleshooting - Philips 20PF9925/12S Service Manual

1. General Features
No. Symptom
1 No screen
2 Dark screen
3 Broken OSD display
2. TV and external input
No. Symptom
4 No sound
- Speaker
- Earphone
5 Video color beat noise
6 Video Jitter

Troubleshooting

Cause
Input error of inverter connector
P502 and Pin 21 connector
being slipped out
Cracked components and
soldering at tuner board
1) Defective LCD lamp
2) Defective inverter
3) Input error of inverter connector
Defective the font rom of IC501
Cause
Defective Reset IC of IC902
Defective MSP3410D of IC901
Defective B+(8V,5V) of IC903,904.
Soldering IC201 and IC502,IC501
or masking it short.
P501B Pin20 connector defective.
Check Point
1) Bend the pin legs of P802B connector -> recheck
them
2) Check and repair the IC806,807 SI4925,IC801
SI786,IC803 SI4808.
1) Check and fix P503B connector
2) Check and fix the components at P502 LCD module
and at main board.
3) Check Pin50.
1) Check and repair tuner board and main board
2) Solder Q101.
1) Replace the inverter
2) Replace the LCD lamp
3) Check the connector input.
Check and replace the font rom of IC508
Check Point
1) Check volume and speaker
- Sound comes out only when being inputted into Audio
L/R
2) Check after replacing IC902
3) Replace IC901
4) Check and replace B+ of IC903,904.
Check and resoldering.
Check the P501B Pin20 connector and repair.