TROUBLESHOOTING HINTS
1. No Character
No Character
Are the
Contrast &NoChange the Contrast &
Brightness control to
Brightness Controls
maximum
maximum?
Yes
Is wholeNo
Refer to
screen bright?No Raster
No Raster
Yes
Is CRT
Yes
Cathode (Rk, Gk, Bk)Check the peripheral circuit
signal levelof CRT Board
normal?Rk, Gk, Bk
About 45Vpp
No
Is the
output signal of theCheck the video output
Yes
(pin 21, 24, 26) pre-ampcircuit and IC803 (pin 1, 3, 5)
(IC801, KA2500)and their ambient circuit
normal?
No
Is 12Vdc lineNoTrouble in 12Vdc line
normal?of the Main PWB
Yes
Is clamping No
Check the clamping pulse
pulse (pin 18 of IC801)
circuit
normal?
Yes
Is input signalNo
Check the signal cable
normal?
Yes
Trouble in IC801 and
its ambient circuit
15 |