IF no picture still then I'd say hardware failure.
I'm also thinking that might be the case. Kinda reminds me of the problem I had with my Edision OSmio Plus a few years ago. It would boot up, I would get the logo but then black screen. I eventually found that if I navigated to the video mode menu and just changed anything, it would usually start working fine - and that this trick had better success on some TVs than on others (quite difficult on my old Sony Bravia from 2007)
Fast forward a few years, the Sony TV eventually died, and we replaced it with a new LG. The MioPlus liked that one much better than the old Sony and most of the time I did not even need to use the menu workaround, it would just work fine.
now we have moved the LG to the bedroom and bought a new Samsung OLED (S84 something), and so far the MioPlus has worked fine, no video problem.
So I'm thinking that maybe the HDMI port is damaged, but depending on the TV and how it handles the HDMI protocol handshake, it may or may not find a mode that works
Maybe it's the same here for Jim's receiver and I would suggest trying it on a different TV