26

 

ACER G24

 

 

 

Go to cover page

5. Troubleshooting (continued)

5.7Checking the interface circuit of sync signal

5.7.1Checking the control circuit of horizontal sync pulse

 

 

 

 

 

 

 

 

 

 

Failure Point

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.

Video cable is defected.

Check the horizontal

 

 

 

 

2.

Printed wire is broken between P304 pin13 and I314 pin46.

sync signal on I314 pin46

 

 

NG

 

 

3.

FB305, R364, R363 is open.

 

 

 

TTL level

 

 

 

 

4.

R371, C336, D305 is short.

 

 

 

 

 

 

 

 

 

5.

I311 is defected.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OK

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Proceed to “5.8 Checking the

 

 

 

 

 

 

resolution change IC movement”

 

 

 

 

 

 

section

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5.7.2 Checking the control circuit of vertical sync pulse

Check the vertical sync

signal on I314 pin47 TTL level

 

 

 

 

Failure Point

 

 

 

 

 

 

 

 

1.

Video cable is defected.

 

 

 

2.

Printed wire is broken between P314 pin14 and I314 pin47.

 

 

 

3.

FB306, R368, R369 is open or more than one component.

NG

 

 

 

 

4.

R370, C335, D303 is short.

 

 

 

 

 

 

5.

I311 is defected.

 

 

 

 

 

OK

Proceed to “5.8 Checking the resolution

change IC movement” section

Page 27
Image 27
Acer MB243WABNS service manual Checking the control circuit of vertical sync pulse