Electrical Troubleshooting Guide; Power Check Flow - LG DKE573XB Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

1. Power check flow

No 3.3VA
YES
NO
Is the FR101
Normal?
YES
NO
Is the D105/ D106/
D107/ D108 Normal?
YES
NO
Is the Vcc (about 8.7V)
supplied to IC101 Pin2?
YES
NO
Is the D121
normal?
YES
NO
Is there about 2.5V
at the IC103 Pin1?
YES
NO
Is the D123
normal?
YES
NO
Is the D125
Normal?
YES
Power Line of Main
PCB(DVD) is short
Replace the FR101
(Use the same ICW)
Replace the D105/
D106/ D107 /D108
Check or Replace
the IC101
Replace the D121
Replace the IC103
Replace the D123
Replace the D125
3-2
No REG 5.0V
YES
NO
Is the Vcc(=5.6V) sup-
plied to Q126 Collector?
YES
NO
Is the Vcc(=12V) sup-
plied to Q126 Base?
YES
Check or Replace
the Q126
No 12V
YES
NO
Is the Vcc(=14V) sup-
plied to Q123 Collector?
YES
NO
Is the Vcc(=12V) sup-
plied to Q126 Base?
YES
Check or Replace
the Q123
Check or Replace
the D123
Check the 'PWR CTL
"H"' signal from µ-com
Check or Replace
the D125
Check the 'PWR CTL
"H"' signal from µ-com