LG CM9750 Service Manual page 52

ELECTRICAL TROUBLESHOOTING GUIDE
B
pin47~50
of IC202, FL/FR± signal
OK?
YES
IC203, IC204
FL/FR audio signal OK?
YES
Check IC203, IC204.
pin13 of
IC700, IC701, IC702, IC703
FL/FR audio signal OK?
YES
Check IC700, IC701,
±66 V, -12 V, ±5 V
Power voltage OK?
YES
Q705, Q706,
Q707, Q708, Q711, Q712, Q713,
Q714 OK?
YES
Check Q705, Q706, Q707,
Q708, Q711, Q712, Q713, Q714.
NO
Check IC202.
NO
NO
IC702, IC703.
NO
Check SMPS.
NO
Check speaker cable connection.
3-33
NO
Check IC202.
NO
Check IC205.
NO
Check IC705.
NO
Check SMPS.
NO
Check Q717, Q718.
OK
pin45, 46 of IC202,
SW1± signal OK?
YES
IC205
SW1 audio signal OK?
YES
pin13 of IC705
SW1 audio signal OK?
YES
±66 V, -12 V, ±5 V
Power voltage OK?
YES
Q717, Q718
OK?
YES