Hey David, have you checked the monitor adjustments yet? Maybe the brightness and/or screen pots are turned way too far up? I'm not that great at troubleshooting though - my experience working on games is still pretty limited. You might want to try the "Repair and Help" forum at KLOV. That's a better place for help on arcade game hardware generally. You could also start a thread in the Restorations section here to document your progress, like I've done.
I'll check later tonight on the test switch like I promised. Hopefully in around 3 hours (have plans directly after work).
Can't wait to see progress bringing it to life!