I had the game ROM go bad on my data East Simpsons with a Rottendog board in it.
The sounds had been off sometimes playing jackpot music sometimes not sometimes getting stuck in the mystery music after the mystery ramp was off. One night while playing it just rebooted itself and lost all the high scores and settings but still worked, then after a few games only the music worked, sometimes the flippers would work during attract mode but not in a game.
Diagnosed it as a bad EPROM chip from the data East pin wiki site, ordered a new one and all the problems went away. So I guess sometimes they do slowly go bad and then stop working