OK, let's see what we have here...

During the transport, the inner monitor bezel has moved. Also a good opportunity to clean that area...

I believe this is the original commando monitor


Let's also clean the main bezel, which is a simple piece of cardboard printed


Let's have a look inside the cab...

Original Capcom board, but weird they used this kind of adapter?

Sooo... the game works...

...but ... no sound! Basic checks done (speaker, continuity wires, dip swith, knob volume...) still no sound!
Must be a PCB issue.

I've just bought another board. Waiting for delivery....