Amp Power Supply On Smps Board - LG BH5140S Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE
No 14 VA.
Is F901 normal?
Is TH901 normal?
Is BD901 normal?
Is the VCC (11 V ~ 25 V) supplied to IC901 pin5?
Power Line of MAIN PCB is short.

2. AMP POWER SUPPLY ON SMPS BOARD

No 31.5 V / 25 V
Is the P-CTL normal?
Is the VCC (11 V ~ 25 V) supplied to IC901 pin7?
Is IC901 normal?
Is Q902 normal?
Is D955 normal?
Power Line of MAIN or AMP PCB is short.
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
Replace F901. (same fuse)
NO
NO
NO
NO
NO
NO
NO
NO
2-42
Replace TH901.
Replace BD901.
Is D953 normal?
YES
Check or replace D953.
Check the MICOM IC.
Is Q901 normal?
YES
Check or replace Q901.
Replace IC901.
Replace Q902.
Replace D955.