Acer A221HQV Acer A221HQV LCD Monitor Service Guide - Page 32

30 ACER A211H/A221HQ Go to contents page 5. Troubleshooting (continued) 5.1.7 Checking the interface circuit of sync signal: 5.1.7.1 Checking the control circuit of horizontal sync pluse: Check the horizontal sync signal on P302 pin13 TTL level. OK NG Failure Point Video cable is failure. Check the horizontal sync signal on I308 pin 22 TTL level. OK NG Failure Point Proceed "Checking the resolution change IC movement" section. Failure Point 1) Printed wire broke between P302 pin13 and I308 pin22. 2) FB304 , R405 is open. 3) D307 ,R319 or C322 is short. 5.1.7.2 Checking the control circuit of vertical sync pluse: Check the vertical sync signal on P302 pin14 TTL level. OK NG Failure Point Video cable is failure. Check the horizontal sync signal on I308 pin21 TTL level. OK NG Failure Point Proceed "Checking the resolution change IC movement" section. Failure Point 1) Printed wire broke between P302 pin14 and I308 pin21. 2) FB305 or R331 is open. 3) D310,R318 or C313 is short.