[dtvmcdonald]

If I were you, located where you seem to be, I'd try to find somebody with a 100 MHz scope and a signal generator and make up a couple of bias boxes (9 volt battery and 100K or so pot across it and some clip leads, two separate outfits.)

Have the knowledgeable scope guy visit you and start at the antenna and get the B&W signal to the CRT, with the horizontal and vertical oscillators and outputs completely unplugged. The set should be on a variac set so the B+ is not too high and the filaments not too low.

Next try to get the horizontal (and boost) working, still with a signal getting through with the AGC still running on the bias boxes.

Also remember ... this has been said before but its good to be reminded: never, ever, run the horizontal ourput tube with the plate disconnected or no B+ on it and its screen at normal connection. Its OK to run the screen at something like 20 volts if you can find that somewhere. Usually one just unplugs the horizontal output tube.

I had a recalcitrant horizontal intermittent in my CT-100 and that's what I did ...
using the scope on the Horizontal circuit with the AGC set with a bias box showed that its was the oscillator part that was intermittant. It never identified the bad part so I replaced them all, all resistors included, a second time. That fixed it.
I would never ever have figured all that out without scoping with the AGC fixed.