The machine I bought may have died, but others were brought back from the brink. I recently got an empty Mad Planets upright for free, and I'm turning that one into a MAME cabinet too. The guy who gave it to me was trying to get rid of it for about a month with no takers. Who knows, it may have ended up in the dump if I didn't get it.
Into attract mode, push the two joys to up, press the two action buttons and one button of start game, and it will show the credits of the game. After a few seconds, the game will reset. The wait can be stopped pushing the start 1 button.