Upgraded to new mobo and will not post, urgent advice needed please!

[Richdog]

i guys hope you're all well. I have a big problem and I need help please. I just built a friend a PC using my existing parts but with a new mobo and RAM.

• Gigabyte B550 Auros AX v2 - NEW
• Corsair PC3600 DDR4 - NEW
• Gigabyte RTX3090 Gamibng OC - Was working fine last I used it
• AMD 5800x - Was working fine last I used it
• Seasonic Gold 850w - Was working fine a week ago
• Be Quiet 500DX

Basically what happens is:

1. When I plug in the PSU cable and turn on the PSU switch, a little spark appears at the back of the mobo near the IO panel.
2. When I press the power button the fans on all components all spin up.
3. There is no LED or beep or anything.
4. The rear amber RGB of the mobo is on.
5. The PC does not post.
6. We checked all cables they seem fine.
7. I am unable to flash the BIOS.

I am at my wits end here and my friend is bummed so any advice would be gratefully appreciated before I take the PC apart and rebuild it screw by screw. Many thanks!

 

[Richdog]

Rebuild it outside the case on the box the mobo came in. That spark you say you are seeing is a worry! Could have already killed the board and it sounds like an installation issue/incompatibility

Damn I really hope that isn't the case but what could have caused it? All of the hardware is of course compatible.

Can you see any burn marks where spark happens? Sounds like a short, anything touching mobo that shouldn't?

I will check later when I start to rebuild. I didn't see or smell any burning though, just a repeatable spark. I have never had this issue before and do not know what it could be, I didn't do anything out of the ordinary!

 

[Richdog]

I tried taking the mobo out of the case and booting and it still did the same spark of electricity near the back panel. I am sending it back for RMA.

Now I need to test the CPU and RAM to make sure that they still work. What a ******* pain.