LG CM7420 Service Manual page 54

ELECTRICAL TROUBLESHOOTING GUIDE
No AMP Output
Is the
VCC supplied to
IC911 Pin7?
YES
ZD912, ZD913
OK ?
YES
D951, D952
OK ?
YES
Check soldering of CN902.
NO
P-CTRL OK?
Q901,D904
OK?
NO
Replace ZD912, ZD913.
NO
Replace D951, D952.
3-35
NO
YES
NO
YES
Check 3.3 V & P-CTRL.
Replace D904, Q901, PC911.