Computer shutting down 10-15 seconds after powering on. Sometimes gets to BIOS. Help!

[roarkarch]

Hello,
I just shipped a custom built desktop to a customer in California from South Carolina. It was an ebay sale and everything worked fine when I shipped it. The machine had 32gb of 3200 DDR4 RAM but he requested I take 16gb out and discount the price. Which I did. I left the 2 sticks in the proper slots for 2 sticks, reinstalled Windows and everything worked fine. Shipped it out.

Well it arrived today and he is having issues with it shutting down after 10-15 seconds. Sometimes it gets to the MSI splash screen and he can hit DEL and enter the BIOS, but then it shuts down. He seems like a great guy and we've been in contact all day and on the phone and he's working with me to get this sorted out.

One thing he mentioned is that the power supply was a little loose and a couple screws were out in that area when it arrived. He put it all back together and such. But PSU strikes me as potential culprit #1

The other thing is that it's possible that the RAM is acting weird from where I removed 16gb. I say this because it's 3200 RAM but when he was able to get to the BIOS screen one time, it was showing as 2333. He tried to reset the CMOS but it doesn't appear to be helping anything. So when he gets off work, he's going to try booting with 1 stick of each piece of RAM and see if that works. If not, I may just send him the 16gb he had me remove and hope that fixes the problem. But I'm reaching...

So I'm thinking it's power supply or RAM. Either seem likely culprits because of the PSU from shipping and then the RAM from me messing with it. The same PSU is in stock at a Best Buy near him, so I might see if he could get it and then I'll reimburse him if it solves the problem (otherwise return it).

Otherwise, the machine was perfect when I was in control of it over the past 9 months, so I can't think of anything that could have happened or that would have the shutoff effect after 10-15 seconds.

The build is:

Case: NZXT - S340 (Black) ATX Mid Tower Case Razer Edition
Motherboard: MSI - X399 GAMING PRO CARBON AC ATX TR4 Motherboard
CPU: AMD - Threadripper 1950X 3.4GHz 16-Core Processor
CPU Cooler: NZXT - Kraken X62 Rev 2 98.2 CFM Liquid CPU Cooler
GPU: EVGA - GeForce GTX 1080 Ti 11GB SC Black Edition Video Card
RAM: Corsair - Vengeance LED 32GB (4 x 8GB) DDR4-3200 Memory
Storage: Samsung - 960 EVO 1TB M.2-2280 Solid State Drive
Power Supply: EVGA - SuperNOVA G3 1000W 80+ Gold Certified Fully-Modular ATX Power Supply
OS: Windows 10 Pro

Wanting to make him happy! It's an amazing machine and it's gotten off on the wrong foot in California

Happy to answer any other questions or ask him any questions too since he has the machine.

 

[roarkarch]

Just an update as he and I just spent 30 minutes trying to Facetime troubleshoot...

He removed 1 stick of RAM and put one in the far right slot as directed by the manual and the machine stayed on for about 5 minutes before turning off. I could see the lights on the GPU, Motherboard, CPU cooler, RAM all come on (lots of RGB). Then go off. That cycle after removing the RAM was the best it's done.

I watched as the machine turned off sometimes after 1 second, sometimes after 5 seconds, and sometimes after 10. Sometimes it would get to the BIOS. Other times it wouldn't.

He held down the CMOS reset button for 5-10 seconds as directed by the manual. Once with the machine on and once with it off. Didn't seem to do anything.

Really baffled by this. At this point, does this sound RAM, PSU, or something else entirely?

 

[roarkarch]

After doing some more reading, I lean RAM as culprit. Perhaps from removing the other 2 sticks. So I’m shipping him the 2 sticks I removed. Hopefully that solves it. I didn’t realize how finnicky sets of RAM can be.

I’d still like to hear from anybody if there are other ideas. But for now that’s the best path I think.