LG Flatron L1972H - Troubleshooting Guide; No Power Diagnosis

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TROUBLESHOOTING GUIDE
Copyright
2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
1. NO POWER
NO POWER
(POWER INDICATOR OFF)
CHECK IC501
NO
NO
CHECK POWER BOARD,
AND FIND OUT A SHORT
POINT AS OPENING
EACH POWER LINE
CHECK U901(3.3V)
U902(1.8V) LINE
NO
CHECK CRYSTAL(X501)
YES
YES
YES
CHECK J905 VOLTAGE
PIN5,6 (5V)?
IS U901 PIN2(3.3V)
U902 PIN2(1.8V)
CHECK X501 PIN127
PULSE
1
2
13
14
Waveforms
1
J905-#5,6
2
IC901-#2
3
IC902-#2
4
IC501-#127