Checking The Back Light Unit - Acer A221HQV Service Manual

ACER A211H/A221HQ
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5.1.3 Checking the back light unit:

Check the BKLT_EN signal of the
DC input P301 pin 2 at TTL high
Check the BKLT_ADJ signal of
the input P301 pin3 from I308
1) Back light unit of LCD module
2) Inverter Cable disconnect
5. Troubleshooting (continued)
Is +22V supplied to inverter
PWB? (by the power board)
OK
level.
OK
pin102 is a PWM signal.
OK
Failure Point
is failure.
NG
Power board of Inverter part
failure.
1) printed wire broke between
NG
P301 pin2, R304 and I308
pin101.
2) I308 is failure.
NG
Printed wire broke between P301
pin3, R501 and I308 pin102.
Failure Point
Failure Point
Failure Point