Circus Hi Rise / Skeeball Model S help

[Jetkidish]

I have a Circus Hi Rise that runs on a Skeeball Model S board. The game was working great over the last two days, then during the attract the lights started getting "stuck" (they usually cycle up from the bottom to the top). You could still coin up and play, but the game seemed to get more unstable. Eventually it started spitting out tickets and became unresponsive.

I looked at the board and found the socket under U7, the NVSRAM was corroded pretty badly. I tried to clean it and it fell apart. So, I replaced the socket, and now the game is completely erratic. Sometimes when plugged in it's dead, other times everything lights up and the bell goes off, and sometimes it'll make random noise.

Everything I've checked so far seems good, but I'm thinking maybe it's a bad CPU or something.

A handful of the chips on my board have been sanded off, and I don't see anything in the manual or schematics. If anyone has any info on this board, I'd appreciate it.

 

[gutz]

Going off memory here from a few years ago, might be off - all the chips numbers are available in the manual for later model S controller games like scat cats, alley hoops, etc. but they are the newer version of the chips (cmos level with extra letters in the chip number vs the ttl level that you want)

 

[Jetkidish]

Seems to have been the RAM
Digikey still has replacements

New chip and the game lives again