Question Help! The motherboard suddenly went black screen.

[lcldiy]

I cut two 7900x motherboards. At first, everything was working fine. Then disconnect the video cable, and when reconnecting it, the screen goes black but there is sound. The sound is functioning properly. It's a black screen, and the composite video signal is also black. Both motherboards have the same problem. After cutting, everything was normal. After using them for a while, suddenly the screen went black and there was a sound. Was the video chip damaged by static electricity?

 

[Kowabungus]

If two boards are doing it I'd say try and first rule out the common denominators. What are you using to power them / what display are you using?
If able to provide some photos fully wired up that may also be helpful for us to look at!

Thinking unlikely in your case, but I've ran myself crazy before with a black screen only to realize I accidentally swapped video output settings at some point. Blindly swapping between them using the guide below is maybe worth a shot if you haven't already tried: