Okay. I readjusted the controls, this time paying attention to just what I was adjusting. vertical and horizontal controls work fine, but I can't get horizontal or vertical to lock in place.
Here's a video of it now:
http://youtu.be/2agduuDwDL4
The control on the back that's missing a knob is labeled 'VERTICAL LIN". Not sure what it does or if it's related to why the image won't stabilize. Perhaps there's a weak tube inside the set.
If it's something easy that I can fix, I might give it a go, but again I'm more interested in giving this set to somebody more familiar with tube TV's.