Samsung Plasma Vsc low.

[kartwood]

I am working on a Samsung Plasma. Something like HP-T42XX. (don't have it handy)

Sound, no pic. Vs, Va Ve okay, Vsc comes up for a split sec then goes to about -20. Removed both Y drive boards, no change. If I disconnect the ribbon between the Y-main and the Logic, Vsc comes up to spec voltage. I will try to find a good logic pwb to try.

I have been able to swap out the Y-main with a (hopefully) good one so  I'm less inclined to suspect it.

Thanks for any ideas!