I tried a different ion trap magnet. Bingo

Maybe the first one I tried is weak ?
A little twiddling of the Hor. Lock coil on the back finally got me a stable picture
Just in time to catch the Outer Limits
Very bright picture!
There are some faint vertical lines on the left side. The set came with a 6AX4 installed in the 6W4 socket so maybe that's the cause. Or maybe the horizontal yoke cap. I'll try adjusting the Hor. Drive too.
I'm glad I can sleep in late today