I bought a faulty Pac-Mania mainly for spare parts but I gave him a chance and tried to repair it
The game was missing sound roms, after replacing them, game booted and you could play but the screen was totally a mess.
After some blind testing I started test all socketed custom chips and rams against new ones and I eventually found the culprit
in the “text” ram @L5!
It was so bad that it totally covered the screen with junk graphics
Replacing it fixed the game 100%