I played last night. Everything was fine. This morning I powered it on, heard an pop (like an electrical arc pop), and no display. I powered off, opened the backbox a got the smell of ozone - no BURN smell, just ozone. I disconnect the display, powered on, and it seems to function otherwise.

Given the pop and ozone, I would expect to be able to find a visible trace of an electrical burn. But so far I see nothing.

I tested voltage going to the board, and it SEEMS right. There is one connector that I am having a hard time identifying on the schematic; but it measured voltage. I don't THINK there is any high voltage going to the display panel.

Do you think the pop/ozone is coincidental? Any advise on how to proceed?

Oh, I forgot to mention, no fuses blown.

OK. Nevermind. I was able to follow the connectors back to their source. Sure enough, there was a fuse hidden behind a bundle of wires - and it WAS blown.

Replaced the fuse, and it immediately blew when I powered it up again. So it wasn't an anomaly. I have taken the display apart, and nothing is visibly obvious. Now I am trying to check things out with my multimeter.

The fuse is for the power that goes to the display. The schematic says +12V; but I measure with the display disconnected and it reads +18V. It seems likely that would cause a component on the display board to burn out. That means I have two problems: correcting the bogus voltage from the power supply; and locating/fixing the damaged component.

Any help/guidance would be appreciated.

Thanks. I've seen a couple of posts on that. And there's even this https://pinside.com/pinball/forum/topic/who-needs-a-sega-192x64-replacement#post-3296132

I wish I was better at diagnosing electronics (I even have an EE degree - but I have never been an EE professionally - I am a software engineer). I find it hard to believe that I couldn't replace a couple of transistors and/or diodes and resurrect this thing.

Maybe I'll upgrade, continue to investigate, and have two working DMD when I'm all done.