Acer AC901 Manual page 21

6-4 No Vertical Scan (Raster is one horizontal line)
No Vertical Scan
Check
I301 voltage of
pin 1 is 12V, pin
2 is 37V and
pin 4 is
-14V?
Yes
Check
pin 5 O/P waveform
at I301
Normal
Check
pin 6, 7 of I301
waveform
Still no vertical scan
Check or replace CRT
Check or replace
N o
I301.
Abnormal Replace I301