Question power button sometimes doesn't work

[bastg]

Hello!
I've been asked to troubleshoot a system that doesn't always properly shut down.
I've tried many things, but so far none have worked. Here is what I know:

• The issue only happens after the computer has been running for a while
• When the issue happens, shutting down via the OS or PSU works. After that, the power button will not work for a few minutes.
• A physical issue with the button or connectors was my first guess, but:
  • Using a screwdriver to bridge the power button pins on the motherboard has the same effect
  • I've also tried with connectors that have bare wires at the other end, to be sure I don't bridge the wrong connectors in some tests
• The solder joints for the power button pins seem fine, and they always work to start the system when it has been inactive for a while.
• A virus or update issue seems unlikely:
  • The computer is not connected to the internet (no wifi card and no ethernet connected),
  • There is one usb port, exclusively used for connecting a keyboard, and a bluetooth mouse
• I've checked the components I can access for bad connections and have found none (SATA connectors to storage, power button pins, PCIe cards, RAM modules, etc...). Accessing other components will require taking apart the whole thing, I'd like to avoid that if possible
• I have tried disabling fast startup in windows, that didn't help.
• Sometimes, when shutting down (Through the OS or the button), the CPU fan goes to a high RPM and stays there until I turn off the PSU (I've waited for about 10 minutes)
• When the "incomplete shutdown" issue happens, the power button won't do anything for a few minutes
• There doesn't seem to be any overheating going on: fans run at a low RPM throughout (except during the "incomplete shutdown issue"), I can't feel anything getting warm, and there is no alarming smell.
• BIOS error messages sometimes appear when booting:
  • "The current BIOS settings do not fully support the boot device"
  • "no boot device detected" (or something similar: I'm translating this one from french)
• I've put a camera on a tripod and took photographs of the pins when the button works, and when it doesn't. Nothing seems to have physically moved between the two.
• The system has been working without issue for a few years now, and hasn't been modified recently
• I don't know the motherboard model: system info shows "Unknown", and I'd have to disassemble the whole thing to find it

Can anyone help me figure out what's going on here ?
Thank you very much!

system info:

• OS: windows 10 family x64 10.0.10240
• CPU: Intel(R) Core(TM) i7-4790 @3.60GHz, 3601MHz, 4 cores, 8 logical processors
• Motherboard manufacturer: ASUSTek Computer INC
• Motherboard model: Unknown
• BIOS: American Megatrends Inc. 2501, 22/07/2015
• SMBIOS: 2.7
• RAM: 4x8 GB
• Graphics: NVIDIA GeForce 210
• Network: Realtek PCIe GBE Family controller
• Audio:
  • Nvidia High definition audio
  • Nvidia virtual audio device (Wave extensible) (WDM)
  • Realtek High definition audio
  • RME HDSP AES
• storage:
  • Smamsung SSD 850 EVO 250GB (contains a system partition and the C:/ drive)
  • crucial ct525mx300ssd1: 500GB SATA SSD (D:/ drive, for other data)

 

[Ralston18]

PSU: make, model, wattage, age, condition (original, new, refurbished, used)?

Look in Reliability History and Event Viewer for error codes, warnings, and even informational events that may have captured when the problems occurred.

 

[bastg]

PSU: iTek Desert 750
It was bought new, around 3 years ago, and looks as good as new (clean, no dust, no noise)

Reliability history shows some application, windows, and driver errors, but without much details
Event viewer show:

• taskScheduler warnings:
  • NT TASK\OC GURU II Auto Run
  • OneDriveUpdater
• Kernel PnP warning: "Loading the driver \Driver\WUDFRd has failed for the peripheral ACPI\PNP0A0A\2&daba3ff&1
• One kernel-power error (I suspect this is from when I manually turned off the PSU, when I couldn't shut down the computer)

I can't find any logs whose timing corresponds to the issue

 

[rickypicky5]

Your PSU has a 2 year warranty. A PSU with a 2 year warranty usually isn't very good or reliable. I'd get rid of it ASAP.

 

[bastg]

Ok, I'll have a look at that.
Do you think a faulty PSU could explain my issues ?
If the computer was shutting down unexpectedly, it would make sense, but I don't understand how it could affect the power button...

Thanks!

 

[rickypicky5]

Does the issue only happen when shutting down? Does the power button always work when turning on?

On a side note, the proper way to shutdown a PC, at least as far as I know, is Start -> Power -> Shutdown.

 

[bastg]

Does the issue only happen when shutting down? Does the power button always work when turning on?

On a side note, the proper way to shutdown a PC, at least as far as I know, is Start -> Power -> Shutdown.

The power button always works when turning on "from cold"
I understand that the power button is not the best way to shut down, but in this system or would be complicated to go through the windows menu (there is no mouse/keyboard readily available)

 

[rickypicky5]

I've read through your original post again and my guess is either the PSU and/or the motherboard are causing the issues you are experiencing.