Acer LCD MB243WABNS Service Manual page 26

5.6 Abnormal Plug and Play Operation
5.6.1 Abnormal DDC2 (D-SUB)
1. The host machine isn't communicating in DDC2 mode.
2. The video cable may have defected or may not be established
connection for DDC.
3. The I312 pin6 and P304 pin15 may have no signal or incorrect.
4. The R374, R377 is open.
5. I312 pin6 is short.
6. The input source cable is defected.
7. Check I312 pin5 signal whether if correct.
5.6.2 Abnormal DDC2 (DVI)
1. The host machine isn't communicating in DDC2 mode.
2. The video cable may have defected or may not be established
connection for DDC.
3. The I313 pin6 and P305 pin6 may have no signal or incorrect.
4. The R393 or R397 is open.
5. I313 pin6 is short.
6. The input source cable is defected.
7. Check I313 pin5 signal whether if correct.
5. Troubleshooting (continued)
Confirm the output of serial
data on I312 pin6 synchronize SCLK at
TTL level
OK
Failure Point
Confirm the output of serial
data on I313 pin6 synchronize SCLK at
TTL level
OK
Failure Point
Failure Point
NG I312 is defected
Failure Point
NG I313 is defected
25
ACER G24
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