Electrical Troubleshooting Guide; Power Supply On Smps Board - LG S94T1-S Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

1. POWER SUPPLY ON SMPS BOARD

No 36 VA/ 17 VA
Is the P-CTRL normal ?
Is the VCC
(13 V ~ 22 V) supplied to IC901
pin4?
Is IC901 normal?
Is D951 normal?
Power line of Main or AMP PCB is short.
YES
YES
YES
YES
YES
Check the MICOM.
NO
P-CTRL High- PVDD : 36 V
P-CTRL Low - PVDD : 17 V
Check or replace: Q901, ZD902, ZD901.
NO
P-CTRL High - VCC : 20 V
P-CTRL Low - VCC : 12 V
NO
NO
5-8
Replace IC901.
Replace D951.