Acer WISTRON RB23WABAS Service Manual page 33

32
ACER H233H
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5.9 Checking the interface circuit of sync signal
5.9.1 Checking the control circuit of horizontal sync pulse
5.9.2 Checking the control circuit of vertical sync pulse
5. Troubleshooting (continued)
Check the horizontal sync signal on P302 pin13 TTL
level.
OK
Check the horizontal sync signal on I308 pin 22 TTL
level.
OK
Failure Point
Proceed "Checking the resolution change IC movement"
section.
Check the vertical sync signal on P302 pin14 TTL level.
OK
Check the horizontal sync signal on I308 pin21 TTL
level.
OK
Failure Point
Proceed "Checking the resolution change IC movement"
section.
NG
Failure Point
Video cable is failure.
Failure Point
NG
1) Printed wire broke between P302 pin13 and
I308 pin22.
2) FB304 , R405 is open.
3) D307 ,R319 or C322 is short.
NG
Failure Point
Video cable is failure.
Failure Point
NG
1) Printed wire broke between P302 pin14 and
I308 pin21.
2) FB305 or R331 is open.
3) D310,R318 or C313 is short.