Question Aorus z390 no display and bios code78

Jun 28, 2019
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10
I recently put together a new build and I’m having some trouble getting the bios to come up on my screen.

I9-9900K
Aorus Z390 Ultra
970 Evo Plus M.2 1TB
Vengeance 2X8GB 3200 c16 Ram
Corsair 850 PSU

I don’t have my graphics card yet (rtx 2080) and I’m just trying to get to the bios to install windows 10 off my thumb drive. I’m using the onboard HDMI. So far I’ve tried one ram stick, cmos rest multiple times, checked CPU/board for bent pins. Taken the m.2 out. The board when I turn it on cycles the 3 LEDs in the corner then holds the light at the bottom right (boot). The code reads 78. Could this be a motherboard problem?