1989 Zelda Game & Watch malfunction.

Hi, my 1989 Zelda Game & Watch multiscreen is doing something odd, whenever I push the attack button, it resets the game back to demo play. I've opened it up and cleaned the contacts, which didn't need cleaning, it looks brand new inside, but I'm still unable to play the game. Has anyone had this issue and can help or knows anyone or anything about maybe repairing this?