Question PC does not POST after restarts (ASUS Prime Z790-V WIFI)

[Marando]

New build, and everything is fine with a cold boot. Absolutely no issues in Windows. If I restart (or shutdown), either from Windows or from the BIOS by saving a setting, the system hangs and does not POST. In order to boot I will have to switch off the power supply for a few seconds and then turn it back on. Thankfully everything then picks up where it left off, so BIOS settings/flashing will save and Windows updates will continue.

I do not currently have a motherboard speaker, but this article about the Power LED indicates a VGA error as I get the flashing every two seconds: https://www.asus.com/support/FAQ/1046157 I also tried booting without RAM and get the 4 per second flashing, so it seems to be accurate information... but I'll confirm with the beeps once the speaker gets here. But even assuming that is correct I am still at the end of my rope.

• Other similar-ish threads mention this could be Power Supply. I swapped a different one in and it did not help.
• I completely removed the GPU (old 1080) and used the onboard graphics, no change. I thought maybe it was switching from the GPU to onboard after the restarts (and something was maybe wrong with the 12900K CPU/iGPU), but onboard works fine and has the same problem.
• Ran Memory Diagnostics and swapped out sticks just to eliminate the possibility of a RAM issue.
• Toggled CSM on/off and disconnected all drives (since it happens from BIOS I don't even need a boot/any drive to test... just save a setting to restart). No change.
• Disabled Fast Boot/MCE, BIOS is latest version 1601.

Not even mentioning all the crap I did in Windows before I realized it had nothing to do with the problem.

I feel like it either had to be a defective motherboard, or a simple setting in the BIOS somewhere that I've never heard of. Power save/something not ramping up after a restart and blaming the GPU? Any thoughts?

 

[Darkbreeze]

Does it not POST, or does it not boot. Do you get to the point where it begins to load Windows or does it hang as soon as it begins initializing hardware?

 

[Marando]

Does it not POST, or does it not boot. Do you get to the point where it begins to load Windows or does it hang as soon as it begins initializing hardware?

No speaker yet (ordered and on the way) but I think it does not POST based on the Power LED. The monitor never picks up a signal.

 

[Darkbreeze]

So, I would immediately pull the CPU cooler and CPU, and check VERY closely for bent pins on the motherboard. Even a single pin that is even slightly bent or deformed out of place could cause a problem like this while still mostly allowing the system to boot. You may need to use some form of magnification like high power reading glasses or a magnifying glass to see any differences in the pin bed structure. Also check the bottom of the CPU for any gold "pads" that might look compromised. Check the motherboard, both front and back for any leaking or bulging caps or unusual looking areas.

It's definitely not a BIOS setting. There is no setting that would cause this only on a restart or warm shut down and restart. Since you've tried two different power supplies, it's unlikely that it's going to be that as you are aware. I would also unplug all the front panel connections going to the motherboard and then start it using the following method, then restart and see if the problem still happens with the case wiring disconnected. Problems with the power switch or front panel mini board can sometimes cause a variety of unusual problems.

View: https://www.youtube.com/watch?v=FuPZlliGqBw



It would be very helpful if you would please list ALL your hardware specs with exact model number where possible. CPU, motherboard, CPU cooler, memory kit, power supply (Exact models and approximately how long they've been in service), graphics card(s), all connected storage devices, all connected USB devices whether internal or external, any expansion/add in cards aside from the graphics card and any other devices such as third party or integrated RGB/ARGB hubs or lighting.

 

[Marando]

So, I would immediately pull the CPU cooler and CPU, and check VERY closely for bent pins on the motherboard. Even a single pin that is even slightly bent or deformed out of place could cause a problem like this while still mostly allowing the system to boot. You may need to use some form of magnification like high power reading glasses or a magnifying glass to see any differences in the pin bed structure. Also check the bottom of the CPU for any gold "pads" that might look compromised. Check the motherboard, both front and back for any leaking or bulging caps or unusual looking areas.

It's definitely not a BIOS setting. There is no setting that would cause this only on a restart or warm shut down and restart. Since you've tried two different power supplies, it's unlikely that it's going to be that as you are aware. I would also unplug all the front panel connections going to the motherboard and then start it using the following method, then restart and see if the problem still happens with the case wiring disconnected. Problems with the power switch or front panel mini board can sometimes cause a variety of unusual problems.

View: https://www.youtube.com/watch?v=FuPZlliGqBw



It would be very helpful if you would please list ALL your hardware specs with exact model number where possible. CPU, motherboard, CPU cooler, memory kit, power supply (Exact models and approximately how long they've been in service), graphics card(s), all connected storage devices, all connected USB devices whether internal or external, any expansion/add in cards aside from the graphics card and any other devices such as third party or integrated RGB/ARGB hubs or lighting.

I appreciate the follow-up. Although I didn't mention it, I did try reseating the CPU already (first thing mentioned in the Power LED link from OP after all). I did it again and think the CPU looks good:

The motherboard however....

Probably don't even need to point it out, but bottom middle 🤦‍♂️ I don't think I even looked when reseating... would have thought something like that would be DOA rather than this weirdness. I'm tempted to try to straighten it out but not sure I should even mess with it, will probably just have to exchange (got from Microcenter so should be 1-2-3). Dang it!

Thank you for your assistance. I'll update and confirm that the replacement fixed the problem. I'm sure it will.. defective motherboard was my instinct I just didn't think it would be so obvious lol.

 

[Darkbreeze]

Anything, ANYTHING, not right, that is not directly due to whoever owned the hardware making a mistake, or me making one, would immediately get zoomied right on back no matter what they initially had to say. I'd insist. For sure.

I will say straight up, it is SUPER easy to make mistakes with any LGA socket, so, never take anything for granted. At all.

 

[Marando]

Anything, ANYTHING, not right, that is not directly due to whoever owned the hardware making a mistake, or me making one, would immediately get zoomied right on back no matter what they initially had to say. I'd insist. For sure.

I will say straight up, it is SUPER easy to make mistakes with any LGA socket, so, never take anything for granted. At all.

Yup it was no sweat, I only had it a few days so they took it right back after verifying the damage wasn't user error and got me another one.

New motherboard installed and everything A-OK now. Thanks again.

 

[Darkbreeze]

So, clearly, as seen and as you already know, it was a bent pin like I suggested. I had a feeling that was what it was from the start and while it's a drag, it's also a really good thing that it was relatively easy to figure out. Some folks end up spending forever trying to figure out what the problem is. Right on for getting it resolved.