Try reseating the ribbon cables running from DMD to board. That often fixes issues.

It sounds like more than just re-seating cables. Most likely an out-gassed display. The fuzzy or no display is a sign, and clears up after heat/pressure builds
(it will eventually die).

Now if it was just vertical lines, I would be thinking a data problem. You may still have that as well, and/or not enough power to the DMD. Voltage drops.

If you go color DMD, you solve either problem. No out-gassed display, and the color DMD does not consume as much power.

Sounds like to me this is a High Voltage issue on the DMD controller board. Normally when you see that wavy background, the -112v and -100v drifted out of spec, closer to -130v and -118v, or even higher. Do you have a multimeter to be able to test these voltages to confirm?

If it turns out to be a voltage problem as mentioned, you can upgrade to a ColorDMD, which does not use these high voltages, which means you can skip repairing that part of the DMD controller board.

You won't regret the Color DMD. I have on for my Addams, and I just ordered one earlier this week for TOTAN.

I beta tested the LED display for Party Zone. It has a lot of good color that works well with this title.

I have 12 ColorDMDs, and my scores always drop as I find myself looking at the animations too much when I play.