On my Midway Ms. Pacman arcade machine, when I turn it on, the very left part of the screen is near the center and then every other part of the screen is compressed into one pixel. The part that is not compressed into the one pixel is perfectly fine. The controls, sound, and game work fine.
It sounds like the CRT is damaged. I've never seen the inside of one of those machines, but is the monitor something that could be removed and swapped out with the tube of say an old PC Monitor?
Looks like you may also want to check these guys out: http://www.twobits.com/RGB/
They've got a lot of info regarding this.