Any reason why there is a slot for 2 AA batteries on the PCB is that for saving high scores? If so, does that work for every game plugged in the PCB?
The AA batteries are for book keeping. They do not save scores. Remove them. You do not need them for any game at all.
However, Matt Osborn made a high-score save mod for VS. Super Mario that uses the batteries to save high scores. Check it out here:
http://forums.arcade-museum.com/showthread.php?t=176556