Acer X223 X223W LCD Service Guide - Page 26

5.5 Abnormal OSM display adjust problem 5. Troubleshooting (continued) ACER X223W 25 Go to cover page Check the input TTL level whether was changed when pressed function keys on the P306 pin 4, 5 (normal is high level, when push buttom, generated low level plus) OK NG Failure Point 1) Function key wire disconnection. 2) Function key wire is failure. 3) Function key board is failure. Check the input TTL level of I305 pin89, 90 whether was changed when pressed function keys. (Refer to Table 1) NG OK Failure Point 1) Printed wire broke among P306 pin4, pin5; R369 and I305 pin90. 2) Printed wire broke among P306 pin5,R372, and I305 pin89. 3)C386,C388 ,C389,C390 are short. Failure Point I305 is failure.