SEGA DMD dead?

[sharps]

Very strange fault Grasping at straws but I would try to better isolate where fault may be.

E.g. disconnect cn3 on the sound board so that volume potentiometer is no longer connected and see If any change.

If no change disconnect cn2 on sound board to see if display works without sound

Then reconnect cn2 on sound board and disconnect dmd at both connectors and see if sound works without display.

tried all that, even unplugged each connection one by one and all.