Are the Contrast & Brightness Controls maximum Yes
No
Change the Contrast & Brightness control to maximum
Is whole screen bright? Yes
No
No Raster
Refer to No Raster
Is CRT Cathode (Rk, Gk, Bk) signal level normal? No
Yes Rk, Gk, Bk About 45Vpp
Check the peripheral circuit of CRT Board
Is the output signal of the (pin 21, 24, 26) pre-amp (IC801, KA2500) normal? No Is 12Vdc line normal? Yes Is clamping pulse (pin 18 of IC801) normal? Yes
Yes
Check the video output circuit and IC802 (pin 4, 10, 12) and their ambient circuit
No
Trouble in 12Vdc line
No
Check the clamping pulse circuit
Is input signal normal? Yes Trouble in IC801 and its ambient circuit
