Hi,

I really don't know a whole lot, but I'll try:

It's possible that it's being caused by some bad capacitors somewhere on the analog board, maybe? These computers are, for the most part, are in need of new ones pretty much throughout (including the analog board).

Do you think it would it be more likely that the screen is faulty rather than the analog board?

Click to expand...

It seems like it's probably an analog board problem. Although I don't know much about these things, I kind of doubt the screen (or CRT) itself could be at fault.
You could try re-soldering things and see what happens.

Also, this is a wild guess, but if it is the screen, maybe it needs degaussing?

These machines don't have degaussing circuitry built-in (to my knowledge), so it would have to be done manually somehow.

I hope this helps!

c