
5. Troubleshooting (continued)
5.3.5 Abnormal OSD display adjust problem:
OK
NG
Failure Point
1) Function key wire disconnection.
2) Function key wire is failure.
3) Function key board is failure.
Check the input level whether was
changed when pressed function keys on the
CN305 pin 1, 2. (Normal is 3.3V, when push button,
generted different voltage. Pin 1, 2 is 0.69V or
1.65V or 2.11V)
Check the input level whether was
changed when pressed function keys on the I306 pin
58, 539. (Normal is 3.3V, when push button,
genertaed 0.69V or 1.65V or 2.11V)
NG
Failure Point
1) Printed wire broke between CN305 pin 2, 1306 pin 58.
2) Printed wire broke between CN305 pin 1, 1306 pin 59.
3) C366 or C367 is short.
4) R370 or R371 is short or open.
4) R372 or R373 is open.
Failure Point
I306 is failure
OK
51
ACER A211H/A221HQ