Tech Data wrote:

Ok, in case you think they're all the same, I know it's going to be
there on video 1/2 and tuner. If you have good video on Svideo, channel
90, then the comb filter is the problem. If it really is there on
Svideo, then measure the G1 voltage on the crt, but if the pip screen
shows up, that most likely isn't the issue. G1 should be roughly 18 to
22 volts dc.

www.techdata-kicksass.net

Yeah, the Svideo(90) is also white. The PIP will be on svideo and the
image will be black as required, and the background will still be on a
channel playing correct sound on the gray background. Ill tear the
belly of the beast open tonight and see what i can find.