Question Motherboard wont POST while in case?

[Unknown Nerd]

Hello,

I am in the middle of a motherboard swap. I got the CPU / memory / etc. installed. When I plugged the system in, the motherboard power light flashes for about 0.1 seconds and then dies and I can't get it to power on again until I unplug and replug the PSU.

So I pulled the motherboard out of the case and pulled everything out except the CPU, GPU, and 1 stick of RAM and I sat the motherboard on a desk with the anti-static plastic wrap underneath it. It booted just find, recognized the CPU and RAM no problem. Tried again with 4 sticks of RAM. Again no issues.

I rearranged the standoffs on the motherboard so that only the standoffs which match the holes on the motherboard are present, and the others are removed and I screwed the motherboard back into the case. Once again, power on for 0.1 seconds and dies. Any idea how to fix this? Do I need a new case?

Thanks

CPU: AMD Ryzen 3 3990x 3rd Gen Threadripper
CPU cooler: Noctua NH-U14S TR4-SP3
MB: MSI Creator TRX40
RAM: Hyper-X Fury 4x8GB HX432C16FB3AK4/32 (Verified it is on supported RAM list from MSI)
PSU: EVGA 1050G Supernova (1050 W)
No SSDs or drives plugged in for POSTing

 

[Unknown Nerd]

Alright, reporting some more strange behavior. There are 8 standoffs that are recommended in the manual. When they are all screwed in in the case with the PC on its side, I get the 0.1 seconds power on. When I unscrew all of them and leave the motherboard sitting loose in the case on its side, I boot up fine. WTF?

 

[Unknown Nerd]

Nevermind....It's not powering on whether its in the case or not. Very intermittent

Dead PSU or dead MOBO?