Had the set open to try a few things. Re-adjusted the G2 pot on the CRT board which cleared up the cold start flashes.
However, the sudden drop out of picture and sound continues to elude me. Whilst I had the unit open, I rapped on the various PC boards with the plastic end of a screw driver to try and locate a bad solder joint. No drop out. I also rapped on (what I believe was) the Horizontal cap on the "G" daughter board (side of case) without any results. No caps looked impaired ... bulging ... leaky .. whatever.
One thing I have noticed is, when it drops out, I CANNOT control the unit with the remote. I can, however, go up to the set and push the power button, and the relay inside responds. After leaving the power off for a couple minutes, I can turn the set on with either the button on the set, or the remote.
Looks like whatever is causing this is causing me to lose control via the remote .. but then, that returns too.
Schematics would help, but they no longer give those with sets. (this is marked manufactured in Aug. 1990)
When it is working, this is an outstanding TV, with great picture and sound. The annoying drop outs need to be diagnosed and fixed, however.
PS .. there was 1/4" of dust inside the unit, which I vacuumed out. I also replace a yoke to tube rubber support wedge which had fallen down on the main board .. don't think that had anything to do with it.