Acer A221HQV Acer A221HQV LCD Monitor Service Guide - Page 55

5. Troubleshooting (continued) 5.3.7 Checking the interface circuit of sync signal: 5.3.7.1 Checking the control circuit of horizontal sync pluse: ACER A211H/A221HQ 53 Go to contents page Check the horizontal sync signal on CN302 pin 13 TTL level. OK Check the horizontal sync signal on I306 pin 16 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 I306 pin 16. 2) L307 or R324 is open. 3) R327 or C325 is short. 5.3.7.2 Checking the control circuit of vertical sync pulse: Check the vertical sync signal on CN302 pin 14 TTL level. OK Check the vertical sync signal on I306 pin 17 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 I306 pin 17. 2) R325 is open. 3) R326 or C324 is short.