Bought two boards, neither have HDMI output?

Hello!

I was very impressed with a Mu + Lite Board combo I bought recently. So I decided to buy a Sigma and upgrade the Mu to a Full Evaluation Board. Both arrived last night, but neither are producing any HDMI output? My Lite Evaluation board still works fine so I don't think it's my HDMI cable or screens. I tried on two screens just to be sure, but no HDMI.

Today I have arriving a new HDMI cable, as well as USBC to HDMI just to see if it's the board or just the HDMI output.

Both boards appear to boot (Caps/Numb lock toggle when pressed on keyboard), The Sigma does that red light blinking at start and then goes to the normal color, and the Evaluation Board seems to boot fine as well. However, neither are showing HDMI. I also attempted a blind reset bios and the board did restart, so it is clearly responsive, but just no HDMI.

Also, there is a slight electricl hum on the sigma which I was worried might be signs of problems, and occasionally the fan stops spinning.

I wanted to ask if there were any steps to try and fix this, or if I am doing anything wrong, because it seems odd both would not have HDMI. Bad luck?

Again, to summarize: Mu on the Lite Eval board works great! But the full Eval board, no HDMI. Sigma same thing, no HDMI. Both seem to boot, but show no display.