LG CM7420 Service Manual page 53

ELECTRICAL TROUBLESHOOTING GUIDE
No output FL+ / FL-
P-CTRL OK?
YES
D931, D932
OK?
YES
ZD931 OK?
YES
FR931 short?
YES
Check soldering of PN901.
NO
Check 12 V output & P-CTRL.
NO
Replace D931, D932.
NO
Replace ZD931.
NO
Replace FR931.
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