If you are in SoCal, you are welcome to come by and use my Joust as a reference. It took ALOT of work to get mine running, but now it is super stable and stays very cool inside the cabinet. The list or replacements I made in mine is:
New headers on all boards, new connectors on the original harness, replaced all chip sockets with new ones, replaced all the ram with 4164 chips, had to replace the video decoder chips, switched from "AA"'s to CR2025, re-capped all the boards and monitor, using a switching power supply, and shortly replacing the CPO(although this is just a cosmetic).
I think that's it....but there is one down side to all this. The coin slots wont work if you just use the switcher. It cant create the voltage you need to run the solenoids on the coin door. I am working on using a wall wart for that, but since its set to free play its not really high on the list.
I hope that helps, and doesn't seem too daunting. Not every game needs all that. I just really didn't want to have to mess with the game on a semi-constant basis so I replaced all the common failure points.
Mike