any number of component side shit could've got broken. the board itself could be cracked. if the game even works at all, consider yourself lucky.
I would check the amp and caps around it. you'll find this very easily by the black heatsink in the corner.
oh, and your empty board probably won't work either, for totally different reasons. I'm very certain it's empty for a reason, unless you found someone that punted on the roms off a Wrestlemania or 2 on 2 Open Ice. heh