It would be a real shame to MAME that cab. Nice Star Trek c/p's are rare (hell, crappy ones are rare). I've seen nearly a dozen of those cabs and everyone has been a yellowed, converted nightmare.
Have you tried
RGVAC yet? Many helpful guys there. Or just make a new account for Klov. I'd just farm out the repair work on the pcb, find a more reliable montor chassis, and install a switching psu. ST is a tricky game...be patient with it and you'll get it running again.
If you choose to take the easy way out get a
Zector Vector Generator and keep a vector monitor in there. Or, better yet, find the cab a new home and build a Star Trek themed MAME from a more deserving cab.