Acer RA19WAANU Service Manual download pdf (Page 23)

5. Troubleshooting (continued)

5.3 Checking the back light unit

Is +22V supplied to inverter PWB ? (by the

power board)

Failure Point

1) Power board of Inverter part failure.

Check the BKLT_EN signal of the DC input

P301 pin 1 at TTL high level.

Failure Point

1) printed wire broke between P301 pin1,

R303 and I305 pin 88.

2) I305 is failure.

Check the BKLT_ADJ signal of the input

P301 pin3 from I305 pin86 is a PWM

signal.

Failure Point

1) printed wire broke between P301 pin3,

R304,R357 and I305 pin11.

2) Q302 is failure.

Failure Point

1) Back light unit of LCD module is failure.

2) Inverter Cable disconnect

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ACER X193HQ

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Acer RA19WAANU Service Manual Page 23