LG CMS4540F/W Service Manual page 37

AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE
No PVDD
YES
F901 normal?
YES
BD901 normal?
YES
TH901(TH903) normal?
Is Vcc
(10 V ~ 18 V) supplied to
IC911 Pin4?
YES
Q901 normal?
YES
D951 normal?
YES
Is there about 2.5 V
at IC951 Pin1?
YES
Power line of main PCB is short.
NO
Replace F901 (Use the same fuse).
NO
Replace BD901.
NO
Replace TH901.
NO
D903 normal?
YES
Q911 base "H"?
YES
• Check P-CTRL "H" signal from MCS.
• Check PC902.
Check or replace Q911.
NO
Replace Q901.
NO
Replace D951.
NO
Replace IC951.
3-18
NO
Check or replace D903.
NO