LG CJ87 Service Manual page 62

ELECTRICAL TROUBLESHOOTING GUIDE
NO AUDIO CHECK
B
Pin39 ~ 50 of IC600
FL/FR± signal OK?
YES
IC601,IC603
FL/FR audio signal OK?
YES
Pin13
of IC700, IC801 FL/FR
audio signal OK?
YES
±66 V, -12 V, ±5 V
power voltage OK?
YES
Q700, Q701,
Q802, Q803
OK?
YES
NO
Check IC600.
NO
Check IC601,IC603
NO
Check IC700, IC801.
NO
Check SMPS.
NO
Check Q700, Q701,
Q802, Q803.
Check speaker cable connection.
NO
Check IC600.
NO
Check IC602
NO
Check IC702.
NO
Check SMPS.
NO
Check Q706, Q707.
OK
3-33
Pin45, 46 of IC600
SW1± signal OK?
YES
IC602
SW1 audio signal OK?
YES
Pin13 of IC702
SW1 audio signal OK?
YES
±66 V, -12 V, ±5 V
power voltage OK?
YES
Q706, Q707
OK?
YES