PC Losing Power Regardless of Load - PSU Replaced - Problem Persists

[TeaJayAye]

I helped a friend build a PC recently.  It was an upgrade to an old POS system he bought off of FB Marketplace for far too much money.  The only part we salvaged from the old system was a serviceable EVGA 80+ Bronze PSU. I also supplied him with some Corsair Dominator DDR4 out of a known working system.  Otherwise, all parts were bought new. After building, we noticed CPU temps were out of control with a Ryzen 5 3600 on the stock cooler.  I undervolted the CPU temporarily (for a few days of use) until my friend could buy a new CPU cooler. After installing a Hyper 212 Evo, the system ran much cooler. Shortly after the new cooler install, the system began to randomly shut down.  No BSOD.  Just a sudden loss of image and power, though the RGB LED on the motherboard never shut off.  I restored the BIOS to stock settings, figuring maybe it was the undervolted CPU or something like that.  No change.  I then thought it must be the PSU we borrowed from the other system. Moments ago I swapped out the PSU and the problem appears to have gotten worse somehow.  Now I can't even get the computer to post. 

Since the issue has occurred with two PSUs, and the RAM came out of another perfectly operational system, that leaves the CPU, Motherboard, SSD and GPU as the remaining culprits.

I am admittedly VERY weary of swapping in my 1080ti to this system to see if it fixes the problem, though it would eliminate one culprit.  My best guess is the CPU or the Motherboard.  Any tips for solving this problem?  My friend is understandably frustrated as a newbie to PC gaming, and I really want to be able to fix this problem for him. 

Any thoughts are appreciated.

[kb5zue]

It would appear that you're doing a pretty good job so far so just continue what you're doing and I'm sure that you will find the problem.  Like you said, give the 1080 a try and if that fixes the problem, then kudos to you.  If it does not fix the problem,  then you just move on to the nest step with either the cpu or the mobo.

 

Good Luck, take care and be safe.

[TeaJayAye]

1 minute ago, kb5zue said:

It would appear that you're doing a pretty good job so far so just continue what you're doing and I'm sure that you will find the problem.  Like you said, give the 1080 a try and if that fixes the problem, then kudos to you.  If it does not fix the problem,  then you just move on to the nest step with either the cpu or the mobo.

 

Good Luck, take care and be safe.

Thank you.  I now have his 2060 Super in my system, and it is running just fine.  I'm writing this from my system with his GPU in it.  That leaves the motherboard, CPU and SSD.  I don't really have an option for swapping in another CPU or motherboard into his system, as both of my rigs are 8th generation Intel.  Perhaps he should just RMA both the CPU and Motherboard?  What a frustrating experience.  Thank you again for the encouragement and kind words. 

[kb5zue]

You're welcome.  It looks like you're on the right path.

[TeaJayAye]

Double checked his RAM in my system. It's good. Going to swap his SSD into my system tomorrow to see if that works. I'm guessing it's the motherboard, but he can RMA both to be sure.

[TeaJayAye]

Well, I checked everything except the motherboard and and CPU, but I have no way of testing those two components independently. My friend has ordered replacements from Amazon. My best guess is the motherboard is the issue here, but I'll report back for anyone searching for this issue in the future. The symptom was sudden power loss, particularly when stressing the CPU.  The system would simply shut down.  No BSOD, no system hang, nothing. Just a sudden loss of power and image.  I tested the PSU, GPU, RAM, and SSD in my own rig to check, and could not recreate the problem.  This was on an ASUS ROG Strix B450-F and a Ryzen 3 3600 with a Hyper 212 Evo.

[TeaJayAye]

Well, we swapped out the CPU to no avail.  Then we swapped out the motherboard to no avail.  I unplugged the front panel connectors, just to see.  As expected, that did didn't fix it.  I swapped the CPU cooler from a Hyper 212 back the stock cooler, again just to see.  Obviously, no change.  Now, all that's left in my playbook is a Hail Mary.  I'm going to do a fresh install of windows on his SSD.  Cross your fingers for me. 

[TeaJayAye]

Solved. For anyone reading in the future, two Asus ROG Strix boards a B450 and a B550 wouldn't post with known good RAM in slots A2/B2, which the motherboard manual recommends for a two stick dual channel configuration.  I ran a single stick in A1 and it worked. Then I relocated the fan on the Hyper 212 Evo to the other side of the heatsink and installed the second stick in B1. Worked fine. Going to run Realbench overnight to check stability with a RAM overclock. Man, what an adventure.