I presume there's no native Windows game that will run on Windows 10 that can use the MT-32, hence you're presumably running DOSBox with MIDI passthrough? Perhaps the Windows enumeration for devices has changed, and DOSBox is no longer sending to the correct MIDI interface? edit: Whoops, obviously …

I hope you can get it fixed! I haven't used my MT-32 in ages. I've been wanting to hook it up to a system for some retrogaming, but I kept putting it off. If they are prone to certain failures over time, I'd like to learn of them as well. Good luck. I'm hoping I can fix it too! When I get a wild …

I popped the cover off to make sure there wasn't anything obvious. I'm sort of leaning towards cold solder joints which would require removing the board and reflowing. The jacks are slightly loose, but that could be normal. I may pop the board out and have a look.

I actually went to play some old games tonight, and everything seemed to work fine right up until my MT-32 remained completely inactive. I have it connected via a USB-MIDI adapter on my Windows 10 PC. I run all my games through DOSBox and have never had an issue playing any of them before. I tried …