Are the Contrast & Brightness Controls in OSD menu maximum? Yes
No
Change the Contrast & Brightness control value 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
Check the peripheral circuit of CRT
About 30~35Vpp
Is the output signal of the (pin 14, 16, 18) pre-amp IC801, normal?
Yes
Check the video output circuit and its ambient circuit
No Is 12V line normal? Yes Is blanking pulse (pin 20 of IC801) normal? Yes No 5Vp-p Check the clamping pulse circuit No Trouble in 12V line of the Main PWB
Is input signal normal? Yes Trouble in IC801 and its ambient circuit
