[villagetinker]

CatBrian, just out of curiosity I went looking for a repair manual, and I think I found one, it was free, that is the good news. Glancing through the manual, there are several custom chips (who knows if these are available), and other components that I think have not been manufactured for a few years, this appears to be a 1982 vintage game. Having stated this, I may be able to help you, but if you are only willing to pay $50, this may not even cover the parts.
If you have the original instructions, there is a self-test mode (switch near the coin slot) that will provide a lot of information.
In any case if you are interested, send me a PM with your phone number and we can talk.

Also, on the same Google search, I saw several units for sale, and there are modern alternatives, I have seen a few game controllers with typically 100 or more games preprogrammed, you would need to check to see if this game was included, many of these just plug into an auxiliary input on your TV set, and all of these were well under a $100. Hope this helps.