I didn't suspect an alignment issue because best picture and best sound are spot on. Of course "best" is relative with a picture like
that. I'm using a Radio Shack modulator, the same one I've had for some 15 or so years that has been used with many sets, both black & white and color, old and new. It's also feeding a Muntz set that I recently brought down from upstairs where I use a different modulator. That set is still perfectly tuned. If it weren't it would be an issue b/c the fine tuning is concealed.
The way things have gone with this set anything is possible.
Sounds like it's scope time.
As always, thanks for the advice.