Electrical Troubleshooting Guide - LG LHB976 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

1. MAIN SET TROUBLESHOOTING
1-1.
POWER SUPPLY ON SMPS BOARD
No 3.8 VA
YES
Is the F901 normal?
YES
Is TH901 normal?
YES
Is BD901 normal?
YES
Is the Vcc
(11 V ~ 25 V) supplied to IC901
pin4?
YES
Power line of MAIN board is short.
No 12 V
YES
Is the
Vcc 14 VA supplied to IC151
pin2?
YES
Is there
'H' signal at IC151
pin1?
YES
Check IC151 and replace.
NO
Replace F901(same fuse).
NO
Replace TH901.
NO
Replace BD901.
NO
Is D922/ D923 normal?
Check or replace D922/ D923.
NO
Check 14 VA on SMPS board.
NO
Check P_CTL from μ-com.
2-98
YES