Pandaminer Troubleshooting question

I recently purchased two used Pandaminers that I’m going to setup for RVN. When I turn them on everything seems good, but my monitor connected with HDMI shows no signal with the machine running.

Anyone have experience with these that could help me with what’s going on?

Seller thought maybe newer monitor could have issue with these. I’m relatively computer literate I’m just not finding anything to help with troubleshooting this. Thank you!