[SOLVED] Brief flash of light and a small pop every time PC turns off.

[absxiith]

Hi,
Every time my PC shuts down [Fast Boot disabled in Power Options], there is a small pop sound and a brief flash of light from my peripherals,namely my keyboard. It does not affect the system's functioning in any way and it boots up fine. The issue I am facing is that my keyboard's keys (connected to a USB 3.0 port) stop working. It has happened with multiple keyboards. Some details as to the problem and my PC's specifications-

1. The small pop sound is also heard whenever powering on the system.
2. No performance issues. No heating issues [monitored with HWiNFOx64].
3. BIOS is set to load optimised defaults*.
4. Windows 10 v 21H1 [Fully updated]
5. Not sure if the present power socket in the wall is earthed or not.
6. Thrustmaster TH8A connected to USB 2.0 port gives a slight shock when touched.
7. The flash of light appears after about 2-3 seconds. It is very brief and apparently, it appears when the system sort of completely shuts down.

CPU - AMD Ryzen 5 3600.
Motherboard - Gigabyte Aorus Elite B450 [BIOS version - F50] *Erp value changed to power off USB devices after shutdown.
RAM - 32 GB Corsair DDR4.
GPU - Zotac GTX 1660Ti.
PSU - Corsair TX 850M .
Keyboard - Corsair K55.
Mouse - Logitech G402.
[Edit : ]
Storage - 500 GB Crucial NVMe SSD + 1TB Western Digital 7200rpm HDD + 2TB Seagate HDD.

M/B and mouse are connected to USB 3.0 ports directly.

Any help would be appreciated.

[Edit : Very poor cable management inside case but I am sure no loose cables are present.]

 

[geofelt]

#6 is the first item of concern. No way should you get any shock from anything.

#5 would be the first thing to check. There are cheap ground testers that.
Here is an example:
https://www.amazon.com/Electrical-R...ocphy=9011560&hvtargid=pla-569358703601&psc=1

In Europe it might be different.

#1 Is the pop sound coming from a speaker, or from a component?
Put a paper tube to your ear to try to locate the sound.

 

[absxiith]

Thanks for your response.

For 5 and 6, I have called an electrician tomorrow to check the socket.
I have also mounted the TH8A to a wooden mount recently so the shock is not that apparent but yes, the moment I remove it from the mount, the shocks are back. However, it seems to be a sort of residual build up charge since it gets less distinct while repeatedly using the shifter and gives a major shock only when I start using it again after some time .

For 1, I have to check since I am using a headset and speakers. The speakers are off when booting up the system. It is most probably from a component.

[Edit - The pop is more like a click when the power button is pressed and it seems to be from the power button itself. I also booted up the system with the speakers on to check. There are no beeps but the RGB LEDs on the whole system turn red before resuming the bootup process. It seems as if the BIOS resets itself and then is loading some custom profile with every bootup.]

 

[absxiith]

Fixed. Mods may please close this thread.

 

[geofelt]

Fixed. Mods may please close this thread.

What was the fix?

 

[absxiith]

What was the fix?

The switch of the socket to which the system is plugged in was faulty. There was some way to go before it was "fully" on. Also a power strip attached for some peripherals had gone bad.
It took some time to figure out. Nothing wrong with the system.