Read LG 42PT350B-SG (CHASSIS:PB12K) Service Manual online
6. RGB Video Trouble Shooting
Check Signal Format
Is it supported signal?
Y
Check RGB Jack P900
N
Y
Y
Check RGB Cable
Replace Jack
Check RGB Signal
R166,R168,R170
N
Replace It & Recheck
Y
Check Sync Signal
N
Replace one of R163/R164
& Recheck
Y
Check EEPROM (IC901)
N
Replace it or re-burn
& Recheck
Y
Maybe Mstar S7LR(IC101)
has problems
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