Acer AL2002 AL2002 Service Guide - Page 44

8 ACER AL2002W Go to cover page Abnormal OSM display adjust problem Appendix 4: Troubleshooting Check the input TTL level whether to change when press the function keys on the P307 pin3, pin4 (normal is high level when to press button, the level will be changed.) Failure Point: NG 1. Function key wire is disconnected. 2. Function key wire is defected. 3. Function key board is defected. OK Check the input TTL level whether to change when press the function keys on I306 pin114 and pin115. Failure Point: 1. Printed wire broken between P307 pin3 and I306 pin114. NG 2. Printed wire broken between P307 pin4 and I306 pin115. 3. R368 C382 R369 C383 C387,C388,C391 or C392 is short. 4. R380,R383,R378 or R379 is open. OK Failure Point: I306 is failure