Default audio output may be a screen
What it means
Your cab's sound may currently be coming out of a screen instead of your speakers.
Why it happens
Cab owners report that Windows occasionally resets the default playback device to a display's HDMI audio output on boot — this can recur after any reboot or GPU/monitor change, not just once.
How Pincab Toolbox detects it
The name of the currently-default Windows playback device matches a pattern typical of display/HDMI audio outputs.
Check your own pincab
Pincab Toolbox is a free Windows scanner for Visual Pinball X and PinUP Popper. It finds and explains problems like this one. No account, no telemetry.
Download for freeCovered: Visual Pinball X (10.x) and PinUP Popper. Not covered: Future Pinball, Pinball FX, Visual Pinball 9 and the other frontends (PinballX, PinballY).