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Asus Zenith II Extreme X399 - Random Immediate Power Off and won't Power On

Level 9
Setup :

Asus Zenith II Extreme X399 – Bios version 1701 (also happened on 1601)
64GB (8x8GB) DDR4 Corsair 3200mhz
AMD 3970X Threadripper
Corsair AX1200i PSU
2 x 2TB WD SN850 SSD
6 x 12TB WD Drives
Asus RTX 4090 TUF
Lenovo 9460-8i Raid Card
Corsair H150i Cooler
4 additional Corsair Fans

Problem :

Motherboard occasionally abruptly powers off with no notice.
When pressing the power button, nothing happens.
The board has power, but does nothing.
Turning the power off at the wall for 10 seconds, so the board powers off fully, and then powering back on will put the board into a boot loop.
Board will power on for half a second, then immediately power off and then power back on in a loop.
Eventually the board gives up and stays off with the power button non-functional.
The START button on the board also does nothing.
Eventually, after leaving the board completely off for 20 minutes, it will power on.
Some time later, maybe minutes, hours, days, weeks the process starts again.

Video of issue :

Steps taken :
1. Removed all cables and refitted – same problem
2. Removed all cards, cables, etc… and tested without re-installed - same problem
3. Removed front panel and USB connectors, saw this in a forum post somewhere – same problem
4. Removed all memory, except 1, and rotated memory – same problem
5. Checked PSU – All good, same problem
6. Checked Temps – highest chipset temp was 72c, I understand the cut off is over 80c
7. Checked CPU torque screws, all good – same problem
8. Running a test with all fans at 100% to see if that helps

Does this board have any diagnostics to say why it powered off and won’t boot ?

Level 9
Disabling Q-Fan control for the Chipset fan, which makes the Chipset fan run at 100% appears to have stopped the random shutdowns.... for now.

What I was not seeing was any overheating of the chipset, which was peaking at 72c, it now peaks at 66c.
Reading the tech specs, the critical temp appears to be 93c, which I am nowhere near.

Any ideas ?

Problem has resurfaced with the warm weather….

opened the case and blasting a large fan into the case, which is lowering chipset temp to 60c, and all temps look good, but issue persists.

downgraded bios to 1402 and same issues.

any ideas?

really annoyed as my supplier was messing me about and just found out the board is now out of warranty.

Transpires that the Corsair AX1200i PSU has died, and it’s a common issue.

Pending RMA, although it’s a 5yr old PSU but they have a 10 year warranty. Waiting to hear back.

Customer Service Agent

Hello, @kraven72 

Based on your previous description, it is somewhat difficult to identify the current issue.
May I ask if the sudden shutdown issue occurred after any changes were made? For example, updating the BIOS or connecting an external device
Is it occurring specifically when running certain programs or games?
Considering your description (increased frequency of occurrence with rising temperatures), is it possible that the issue is related to overheating?
We recommend checking the connections of your relevant devices, using the latest version of the BIOS, clearing the CMOS to restore the BIOS settings, and observing if the issue persists under default settings.

Thank you.

Ok, rewinding a little.

The issue was that the PC would randomly power off and when pressing the power button the PC would go into a boot loop with "Memory Code 00" displayed on the OLED display. Even when this happened the motherboard LED's would light up correctly and the OLED display would work.

Powering off for 30+ minutes would then allow the PC motherboard to boot.

Disconnecting everything left 3 options :

  1. CPU
  2. Motherboard
  3. PSU

Going through each in turn :

  1. CPU - Was working when the PC was powered off for 30 min or so, however it could easily be a warped CPU because of the size of the chip and the heat generated.
  2. Motherboard - Always had some issue with the board, difficult to get memory to run at full speed, GPU riser cable won't run at PCI-e 4.0 speeds, etc... But with lots of capacitors, there is always a risk of overheating. Occasional bios post issues as well.
  3. PSU - The AX1200i was delivering power to the board as the Aura LED's were all working and it would attempt to power on. Also the OLED display was working, so there was definitely power. Also the AX1200i has a self test, which was showing Green.

Anyway, eventually the board would not power on for hours in that it would power on for half a second and then power off, so I took the whole thing apart and happened to re-test the PSU with the Self-Test and eventually it showed a problem even though it didn't before. It would seem that when the PSU was cold, the Self test would pass, when it was hot it would fail.

Now armed with the new information, I did an investigation online, and it seems these PSU's are known to do this with dry joints on capacitors within the PSU which when warm/hot, cause problems. Even though these PSU's have a Zero-RPM fan mode, I would not recommend anyone using it.

As for the boot-loop as per the video, i had the motherboard set to Power On when connected to power in case of power cuts when i'm away, this was why it would constantly try to boot instead of trying once and then stopping. Even so, the fact that it tried to power on and the PSU Self Test was Green is what stopped me raising a ticket on the PSU.

Replacing the PSU and everything is much much better.

The only thing i'm not happy about is that Corsair refused to replace my AX1200i with a comparable PSU, and would only give me an HX1500i. That's not to say the HX is not good, but at the time, I bought the most expensive AX PSU on the market, and now i've been dropped a tier.