Acer A221HQV - Checking the Back Light Unit

5.1.3 Checking the back light unit:
5. Troubleshooting (continued)
Is +22V supplied to inverter
PWB? (by the power board)
OK NG
Failure Point
Power board of Inverter part
failure.
Check the BKLT_EN signal of the
DC input P301 pin 2 at TTL high
level.
OK NG
Failure Point
1) printed wire broke between
P301 pin2, R304 and I308
pin101.
2) I308 is failure.
Check the BKLT_ADJ signal of
the input P301 pin3 from I308
pin102 is a PWM signal.
OK NG
Failure Point
Printed wire broke between P301
pin3, R501 and I308 pin102.
Failure Point
1) Back light unit of LCD module
is failure.
2) Inverter Cable disconnect
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ACER A211H/A221HQ