Ok, sometimes when I turn on my Dig Dug game I get nothing but the marquee and other lights, but no game. The next day I might turn it on and it works fine. Where should I start?
Not sure about Dig Dug but many of that era Atari games have problems with the edge connector burning up which causes a +5 failure to the board... I would start there.
Pull off the board connector and examine the edge connector.