Acer A221HQV Acer A221HQV LCD Monitor Service Guide - Page 45

5. Troubleshooting (continued) 5.2.7 Checking the interface circuit of sync signal: 5.2.7.1 Checking the control circuit of horizontal sync pluse: ACER A211H/A221HQ 43 Go to contents page Check the horizontal sync signal on CN302 pin 13 TTL level. OK Check the horizontal sync signal on I310 pin 22 TTL level. OK Failure Point Process "Checking the resolution change IC movement" section. Failure Point NG VGA Video cable is failure. Failure Point 1) Printed wire broke between CN302 NG pin 13 and I310 pin 22. 2) L306 or R327 is open. 3) R330 or C331 is short. 5.2.7.2 Checking the control circuit of vertical sync pluse: Check the vertical sync signal on CN302 pin 14 TTL level. OK Check the vertical sync signal on I310 pin 21 TTL level. OK Failure Point Process "Checking the resolution change IC movement" section. Failure Point NG VGA Video cable is failure. Failure Point 1) Printed wire broke between CN302 NG pin 14 and I310 pin 21. 2) R328 is open. 3) R329 or C330 is short.