Same thing happened to ours not long ago. Went out just like that, all of a sudden. Hate to say this but on closer examination, there were what appeared to be two or three solder points that had failed and were arcing behind the small connector at the bottom of the DMD. Worst part: they were unreachable! Couldn't just repair it. Had to bite the considerably large bullet ($475 at Pinball Life) and purchase a new one.
Best Wishes