The shots of cleaning and reinstalling parts didn't turn out too well so I'm skipping right to the finished product in action.
Here's what all was done to it.
Disassembled and cleaned it out
Replaced the bottom
Scrubbed outside of cabinet
Removed and scrubbed all of the wiring, then dried it
Replaced bottom power board with a spare from a parts machine (Galaga)
Rebuilt the original WG 4600
Scrubbed, cleaned, disenfected, and removed funk from all of the other parts
Reinstall all of the parts
Installed switching power supply
Powered the game up and it works.
The kids got to play many games of Bosconian and when finished we moved it into place beside the Ms Pac and Galaga machines.