LG L207WT - Trouble Shooting

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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 U501
NO
NO
CHECK POWER BOARD,
AND FIND OUT A SHORT
POINT AS OPENING
EACH POWER LINE
CHECK IC1(3.3V)
U902(1.8V) LINE
NO
CHECK CRYSTAL(X501)
YES
YES
YES
CHECK J905 VOLTAGE
PIN5,6 (5V)?
IS IC1 PIN2(3.3V)
U902 PIN2(1.8V)
CHECK X501 PIN127
PULSE
1
2
13
14
Waveforms
1
J905-#5,6
2
IC1-#2
3
U902-#2
4
U501-#127