Acer AC501 Manual page 26

B-3. No Vertical Defl ection ( Rester Become A Horizontal Line)
N o vertical
deflenction
C heck U 601 P in 2
about 15V /40V
P IN 4 about -12V D C
C heck U 401 P in 12, 13
output saw -tooth
w aveform
C heck U 601,D 601
C heck D .Y.
Yes
Yes
Yes
Yes
N o
C heck
R 601, R 605
N o
C heck U 401
26
C heck
N o
pow er supply
circuit