Are the video wires twisted ?
Not that I recall, but it's possible, I'll double check that. IIRC, the video harness goes all the way to a connector in the top of the cabinet, then down to a connector on the monitor frame, which branches off to the connector on the monitor chassis itself. Actually, I think there's even a filter board of sorts within the cage. It would be interesting to see what the resistance is through all that. This may also explain why the video is a bit dim, even after monitor re-cap. As HHaase said, it's important for the video to be bright with dark backgrounds.
It will be tricky due to the layout of the PCB cage, but I could also try building a short cable coming directly from the PCB to confirm it's not something in the video generation circuitry itself.
It's probably the power supply.
IIRC, It's just a common 9-pin supply, they're available for $45 in the USA from Happ or Betson.
I had considered this as well, the Japanese version (which I have) uses two separate switchers, one for +5V and the other for +12. I replaced both with new ones as the old ones were beyond repair when I received the machine (same specs as the originals). Oddly enough, there are no transformers in the base of the cab. The monitor has a built in isolation transformer, and there's no filter caps or the like in the cab.
Anyway, I didn't mean to derail your thread HHaase! I'll go stick this back in my Starblade thread. Thanks for the input, guys!