I have this Commodore 1950-B multisync monitor. It is a rebranded AOCCM314 monitor.
A bit atypical of the era, it could sync from 15KHz-35KHz continuously (no click-clunk relays selecting caps), and 50-80Hz vertically.
I haven't worked on monitors in ages, but I am competent enough to figure it out slowly. Just need some pointers.
The symptom it displays is that the picture only displays when the horizontal position is at the extremes, left or right. As I try to center it, the picture goes dim and eventually fades to black.
Does this sound familiar? I'm gonna look at the overall DC supplies first, then look at the CRT grid and cathode drives. What would you check next?
I'm still trying to track down the schematics, but the monitor is much more complex than a fixed frequency RGB job.
I want to think about this before commiting to a repair in my limited space. (CRTs are big!)