The power supply had some really burned connectors and one that was so obviously bad that someone had just yanked the header and soldered directly to the board.
this is normal pinhack repair. the pins and connector burn up and instead of spending 10 bucks and replacing them, people just solder the wires to the board...nothing really wrong with it per se, but it make it a pain in the butt to repair since now your stuff is attached together.
It was a mess that took a while to clean up and it still didn't put out good voltage.
yeah the voltages aren't real critical. as long as the +5v is good and making it to the CPU board processors at 5.something volts... the others can be out by quite a bit before you notice.
The mpu was so alkaline scorched that by the time I figured I had all that neutralized there was no mask in various spots anymore and the chips it drooled through were not happy either.
The battery waterfall was so bad for so long that it made it into the playfield power board too.
i don't know why anyone thought putting batteries that leak onto a board and not in a holder away from everything was a good idea.
So...
After a box with some Rottendog pcbs arrived and I repaired a bunch or wiring harness I was greeted with the themesong from a favorite cartoon show.
ahh the easy, stress reduced way of gettin' 'er done