If you aren't going for 100% original, you might want to consider putting in a modern switching supply and wiring the cabinet as JAMMA, then using a converter (if available for the game you want ... pretty sure there is a PAC-to-JAMMA converter out there).
Doesn't solve the original board issue, but should make life easier in terms of power supply and give you some flexibility if you wanted to ,say, convert the cabinet to Galaga later on.
I haven't thought this all the way through yet, but thought I'd throw it out there.
Cheers.