I have an NEC multisweep monitor. A week ago the raster began to shrink a few millimeters for a second or less. It can happen several times in a matter of minutes. It can happen shortly after startup or when the computer has been on all day.
It can run all day with no trouble. Putting the computer to sleep and waking it, or changing screen resolutions, can cause the problem to start or to stop.
Four years ago, I had similar symptoms with another multisync CRT monitor of another brand. One day it failed suddenly.
Both monitors had relays that apparently cut current to the flyback circuit each time I put the computer to sleep or changed resolutions. Because I put my computer to sleep each time I leave my desk and I play games that change the screen resolution, that relay may have opened and closed 50,000 times in four years.
I'm afraid the relay points have started to burn and one of these days they won't work at all. Otherwise, the monitor works fine and the circuitry looks clean without signs of heating.
Rather than buy a new monitor, I'd like to try a new relay. Where can I get one?