Daewoo CMC-518X, Service Manual

Page: 13 / 61

11
1. No Character
TROUBLESHOOTING HINTS
Yes
Yes
No
About 45Vpp
Yes
No
No
No Character
Are the
Contrast &
Brightness Controls
maximum ?
Is
whole screen
bright?
Is CRT
Cathode (Rk, Gk, Bk)
signal level
normal?
Is
8Vdc line
normal?
Is the
output signal of the
(pin 15, 19, 22) pre-amp
IC801,
normal?
Rk, Gk, Bk
Change the Contrast &
Brightness control value
to maximum
No Raster
Check the peripheral
circuit of CRT
Check the Video output
circuit and IC801
(pin 2, 4, 6) and
their ambient circuit
Refer to
No Raster
Yes
No
No
Trouble in 8Vdc line
of the Main PWB
Check the clamping
pulse circuit
Is
clamping pulse
(pin 23 of IC801)
normal?
No
Check the
signal cable
Is
input signal
normal?
Trouble in IC801 and
its ambient circuit
No
Yes
Yes
Yes
12Vpp