Checking the control circuit of horizontal sync pulse for DVI-D
Appendix 4: Troubleshooting
Checking the control circuit of vertical sync pulse for VGA
Check the horizontal sync
signal on P302 pin13 TTL level
Failure Point:
VGA Video cable is damaged.
Check the horizontal sync signal on
I306 pin89 TTL level
NG
OK
Failure Point:
1. Printed wire is open between P301 pin13 and I306
pin89.
2. FB311 and R321 may be open.
3. R324 and C328 may be short.
4. D306 is short.
NG
OK
Proceed ‘Checking the resolution change IC movement’
section
Check the vertical sync signal on
P302 pin14 TTL level
Failure Point:
VGA video cables is failure.
Check the vertical sync
signal on I306 pin90 TTL level
NG
OK
Failure Point:
1. Printed wire is open between P302 pin14 and I306
pin90.
2. FB312 and R322 may be open.
3. R323 and C327 may be short.
4. D305 is short.
NG
OK
Proceed ‘Checking the resolution change IC movement’
section
Checking the TMDS signal input for DVI-D
Check the TM DS signal
P303 pin1, pin2, pin9, pin10, pin17,
pin18, pin23, pin24
Failure Point:
DVI-I Video cable is dam aged.
Check the TM DS signal
I306 pin72, pin73, pin75, pin76, pin80,
pin81, pin83, pin84
NG
OK
Failure Point:
1. Printed wire is open between P303 and I306 pin89.
2. R332~R335 R338~R341 m ay be open.
NG
OK
Proceed ‘Checking the resolution change IC m ovem ent’
section
11
Go to cover page
ACER AL2002W