Acer NA23WABAS Service Manual page 31

30
ACER V233H
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5.3 Checking the back light unit
5. Troubleshooting (continued)
Is +22V supplied to inverter PWB ? (by the
power board)
NG
OK
Check the BKLT_EN signal of the DC input
P301 pin 2 at TTL high level.
NG
OK
Check the BKLT_ADJ signal of the input
P301 pin3 from I307 pin117 is a PWM
signal.
NG
OK
Failure Point
1) Back light unit of LCD module is failure.
2) Inverter Cable disconnect
Failure Point
1) Power board of Inverter part failure.
Failure Point
1) printed wire broke between P301 pin2,
R303 and I307 pin 124.
2) I307 is failure.
Failure Point
1) printed wire broke between P301 pin3,
R301 and I307 pin117.