Checking The Interface Circuit Of Sync Signal; Checking The Control Circuit Of Horizontal Sync Pluse; Checking The Control Circuit Of Vertical Sync Pluse - Acer A221HQV Service Manual

ACER A211H/A221HQ
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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
Check the horizontal sync signal on I308
Failure Point
Proceed "Checking the resolution change
IC movement" section.

5.1.7.2 Checking the control circuit of vertical sync pluse:

Check the vertical sync signal on P302
Check the horizontal sync signal on I308
Failure Point
Proceed "Checking the resolution change
IC movement" section.
5. Troubleshooting (continued)
pin13 TTL level.
OK NG
pin 22 TTL level.
OK NG
pin14 TTL level.
OK NG
pin21 TTL level.
OK NG
Failure Point
Video cable is failure.
Failure Point
1) Printed wire broke between P302
pin13 and I308 pin22.
2) FB304 , R405 is open.
3) D307 ,R319 or C322 is short.
Failure Point
Video cable is failure.
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.