I have an update. The set STILL has the problem and I noticed something else. when it flashes green for a moment, the set's picture will also flicker for a bit with retrace lines on top of the screen. You never know when it will do it, but it seems it's after the set is on for a half-hour or so. I tapped tubes, and sockets, and it doesn't seem to fix it, or cause it to happen when working. All tubes test good. What circuit or tube should I be looking at ? With my skill level, I HATE intermittent problems.
