Question My motherboard blink a rgb flash after turning off my psu and weird something on my speaker cable

[oktaviorizky23]

Okay, so it's my brother builds, but I need your help.
Here is my brother specification :
CPU - AMD Ryzen 5 2600
GPU - MSI RTX 2060 Ventus
MOBO - GIGABYTE AORUS B450 Pro
RAM - I don't know what brand is but 2X 8GB DDR4
PSU - FSP Hydro GE 750W

okay so the pc works after a years or two. right now my brother is out from my town and I got the free PC while my brother is gone.
weird things happen before this problems. I saw red light on bottom right corner of motherboard, and it's located on VGA. I read such a forum and says that my VGA have some issues. because of that issues, I shutdown my pc cause I don't want some stupid things and bad things happen to my brother pc. After a weeks, I randomly turn off the psu until the motherboard led turn off. I unplug and plug everything on the computer. and then bad things happen.
While I'm unplug and plug my speaker cable, the speaker really give crazy noise and it drive me crazy. I suddenly shake the cable, unplugged, but I saw some flash thingy on the motherboard.
Until now, the motherboard blink a rgb flash every 30 seconds. I don't know what happened, and Im really worried. I need your help guys 🙁

Here's the footage

https://imgur.com/FVq9uj8

 

[Lutfij]

Disconnect from the wall and disassemble the entire system. You should reassemble the entire system making sure that all connections to the components are secured. The other thing to note is, how old is the PSU? You might want to take the system and plug it into another wall outlet and see if the issue persists.

 

[oktaviorizky23]

Disconnect from the wall and disassemble the entire system. You should reassemble the entire system making sure that all connections to the components are secured. The other thing to note is, how old is the PSU? You might want to take the system and plug it into another wall outlet and see if the issue persists.

The PSU still new when my brother build this pc, and this pc age is about 2 years old