PC won't randomly turn on, with a bunch of different symptoms.

[kkauchi]

I have an early-2015 system that worked pretty much perfectly until a few months ago. Then suddenly a bunch of things started happening, almost like organs of someone on their death bed failing one after another...

 

Symptom 1: Restarts during power on.

Sometimes when I switch my PC on, the power LED would light up and fans start spinning; and then two seconds later PC would shut down almost if it lost power. Then a few seconds later it may light up again and start. The cycle may repeat a few times before it actually powers on. However sometimes first time it would not react to the power-on button at all. Sounds like a faulty PSU? Ok but wait for it.

Symptom 2: CPU LED would stay up during POST.

Happens sometimes, but usually right after symptom #1. Sometimes simply restarting would fix it, sometimes I have to cut the power to the PSU and wait for 5 minutes. It could be helping but could be placebo.

Symptom 3: Primary M.2 SSD would stop being detected by the BIOS.

Also usually happens after symptom #1. As with #2, simply restarting would sometimes fix it but sometimes it wouldn't and I just have to wait or try multiple times. Other disks are detected fine.

Symptom 4: Two out four memory sticks would stop being detected by the BIOS.

I have 4 x 8Gb memory sticks: 2x Corsair Vengeance and 2xG.Skill Sniper that I added back in 2017. Now, I have to admit that they are two different brands and work at two different frequencies, however they were working absolutely fine together for almost 5 years.

Symptom 5: Bringing PC back from the standby mode.

Another hint at the PSU issues, often if my PC goes into the standby bringing it back from it would result from it just shutting down as if it lost power. For now I just disabled the standby in Windows.

...

My first thought was a PSU, except I have a new Cooler Master V850 Gold V2 that I purchased less than a year ago. Furthermore, once the PC has turned on, it works great with no issues. No matter what load I put on it, games, benchmarks, it never randomly shuts down or shows any symptoms. Primarily all issues happen during the power-on or during bringing it from standby.

I am sorry this is a lot of text, but I am kinda at a loss. I guess my options are either PSU or a motherboard? The fact that these things happen intermittently and every time it's a different problem makes it very hard to troubleshoot. I have disassembled everything, cleaned it in and out, assembled, for issues to disappear then re-appear two days later.

 

TLDR:

Sometimes PC would shutdown/reboot itself during power-on, and when it does that, it's almost guaranteed it won't load (random components would stop working). Shutting down / restarting a few times helps then no issues until next reboot.

 

 

Motherboard: Asus Z97-A

CPU: Intel Core i7-4790K

GPU: Asus GeForce GTX 970

PSU: Cooler Master V850 Gold V2

Primary SSD: Samsung SSD 970 EVO 1TB M.2 (I also have secondary SSD and two HDDs)

Ram: 2x8Gb Corsair Vengeance CMZ16GX3M2A1600C10R, 2x8Gb G.Skill Sniper F3-1600C9Q-32GSR

 

[kb5zue]

How long has it been since you replaced the CMOS battery?

[kkauchi]

21 minutes ago, kb5zue said:

How long has it been since you replaced the CMOS battery?

It's been a while, so I just replaced it.

 

It have not fixed the issue it seems, as I had to reboot couple times to restore the BIOS settings (switch to M.2 mode, fix the boot priority etc) and I think 2/3 times PC went into a self-reboot cycle AKA symptom #1 which it did at least once or twice.

 

However what's interesting is, every time it would shut down right after the lighting up VGA_LED during POST.

[Xander Cousins]

What slot is the M.2 SSD in? Is it in the one controlled by the cpu or the one controlled by the chipset of the board?

 

The symptoms of the M.2 and the constant restart with cpu led could be an issue with your CPU, was this happening prior to the new PSU or only started after?

[kkauchi]

34 minutes ago, Xander Cousins said:

What slot is the M.2 SSD in? Is it in the one controlled by the cpu or the one controlled by the chipset of the board?

In the past, I used RIITOP NVMe to PCIe Adapter in the SLI slot for faster NVME speeds. However to rule out the adapter issues I have recently switched to the M.2 slot on the motherboard and switched to M.2 Mode in BIOS. So far I have not experienced issues with it's detection but everything else remains unchanged (other symptoms persist).

 

34 minutes ago, Xander Cousins said:

The symptoms of the M.2 and the constant restart with cpu led could be an issue with your CPU, was this happening prior to the new PSU or only started after?

This was after. Late February 2022 is when my old PSU started overheating since the fan died (shutdown when playing games then wouldn't turn on until cooled down, it was an easy issue to troubleshoot), so I decided to replace it. Everything worked perfectly fine until October-ish, is when these issues started popping up.

 

One thing that may confirm issues with the CPU. Right around when these issues started I started noticing weird 1-2 second freezes in games e.g. CS:GO. Once I disabled turbo boost they went away. It was a little weird taking that temperatures were perfectly normal.

 

 

 

 

[kkauchi]

Here is a quick video with the main issue (reboot cycle during power on, which in this case happens right after I press the button). Other issues usually appear after. When that happens chances it's going to boot with no issues are pretty slim so I have to retry multiple times. Apologies about the noise in the background.

[Xander Cousins]

To rule out CPU if possible try repeating the CPU, 

 

 

[kkauchi]

2 hours ago, Xander Cousins said:

To rule out CPU if possible try repeating the CPU, 

You mean re-pasting?.. In this case yes, already tried that. I've disassembled, cleaned and re-assembled everything when this problem first appeared.

[Xander Cousins]

Sorry auto correct, not repasting but re seating the cpu in the socket.

[kkauchi]

On 2/4/2023 at 7:05 AM, Xander Cousins said:

Sorry auto correct, not repasting but re seating the cpu in the socket.

Yeah in that case already tried.