Acer RA19WAANU Service Manual page 23

ACER X193HQ
22
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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 1 at TTL high level.
NG
OK
Check the BKLT_ADJ signal of the input
P301 pin3 from I305 pin86 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 pin1,
R303 and I305 pin 88.
2) I305 is failure.
Failure Point
1) printed wire broke between P301 pin3,
R304,R357 and I305 pin11.
2) Q302 is failure.