It could be the DMD driver board. If you (or a friend) have another game of the same age and style you can swap them one at a time.

Does the noise get louder when the DMD is displaying a lot of lines? If so then it's likely the DMD making the noise and there is nothing you can do for it really besides buying a new one. Usually it can only be heard during attract mode and once the game starts the music and sounds will drown it out. Swap DMD's between 2 machines and see if the buzz follows the DMD. I have a few machines with DMD's that make some buzz and it's really not that uncommon.

The buzzing usually comes from the DMD itself. You should really be able to hear it when the entire DMD is lit. I would purchase a DMD just to have on hand in case it starts to fail.

What's the manufacturer of the DMD? If it's a Cherry they are notoriously noisy. Only solution is to replace it.

viperrwk

I say 100 percent but I will say that every failing DMD (flickering, edges fading) I have come in contact with buzzes a lot.

I've had them buzz for years before failing

I've had new displays break sitting in storage...

If you buy one to replace it 'when it fails', install the new one now and save the noisy one for a 'spare'. Nothing p*sses you off more than pulling out your new DMD you've been saving for the right moment, or that perfect pin, and finding the glass cracked.

I have a few DMD's that make a buzzing sound and none have died on me yet and have been that way for years. He never mentioned his DMD was flickering and had edge fading.

get a new vishay. They are silent.

I meant to say "that i can't say for 100 percent." Didn't want to edit my post after somebody replied. I'm also weary of buzzing displays because if the DMD is failing it can stress out the components on the DMD board.

Try adding extra grounding wires to the DMD (double down on the existing one).

If that doens't remedy your buzzing- either deal with it, or purchase a new DMD, yours is on its last legs.