PC is sensitive to voltage changes

[skdayo]

Hello,

I am no expert on this topic so I apologize for any misinformation. I will try to explain the issue based on what I know/think and information I have found on the web.

I have a custom-built desktop computer. Whenever someone flicks a light switch on the wall in my room or near the room my computer is located in, my computer may react to that in one of the following ways:

• It powers on by itself.
• USB devices like mouse and keyboard stop working for a few seconds.
• I hear a popping noise through my earphones.

For your information, I have two somewhat high-grade DAC/amplifier: one where power is connected to the wall; another one that is powered by USB. Both DACs have the same problem with the popping noise.

I am not quite sure what the problem is but with my limited knowledge, I can imagine that there are several potential issues:

• The switches on the wall produce voltage spikes.
• The PSU in the computer lets this through or does something (bad) to protect the motherboard/devices.
• The motherboard is sensitive to tiny changes in voltage.

I do not really know so I would like to ask for ideas on what is going on here and how I can solve the problem the right way.

I have wondered if a UPS can solve the problem, but I am not sure what my requirements are.

Thank you for any assistance you can provide!

Computer hardware:

• PSU: be quiet! Dark Power Pro 10 (850W)
  
• Motherboard: ASUS Rampage Extreme V (X99)
• CPU: Intel i7 5960X
• RAM: Crucial Micron CT2K8G4DFD8213 (2133 MHz, DDR4, 32 GB)

 

[Mr Evil]

Do you have any other problems with the wiring in the house? For instance do the lights dim or flicker when a high-power device (shower, power tool etc.) is turned on? Is the computer earthed? Do you have another PSU that you can test?

While a UPS might help, it would be better to solve the problem at its source.

 

[skdayo]

...

Thank you for your reply!

I have tried a different PSU now, and I still hear popping noise in my earphones when flicking the light switch. The computer is earthed.

I have asked around the house and nobody has noticed any dimming lights when using other devices. I have not noticed any other problems.

 

[skdayo]

Please feel free to suggest more ideas. Thank you!

 

[Torn Mind]

Bulbs shouldn't be causing major disruption, but if you have incandescent or halogens bulbs, try fitting the fixture with those type of bulbs. They are resistive loads and not inductive loads,

You can also use an outlet tester on the outlet.

Since your USB DAC has the popping noise even with a PSU swap, and DAC should have made it disappear, it could be a variety of things. One, your delivered power is really bad. Two, you PSUs are not doing well. Or three, your mobo is starting to flake out.
A line conditioner can help with the bad mains power. If the PSU or mobo is defective, they will need replacement, of course.

As with all troubleshooting, start with the least invasive and expensive fixes and move on from there. That means the bulbs. If yhe switch are a plain seitch, they really can't do much interference-wise.

 

[Mr Evil]

Try plugging the PC into a different outlet, maybe even one on a different floor, and see if it still happens.

 

[skdayo]

...

Thank you for your reply!

I use flourescent bulbs. I am not sure about the quality of the electricity from the outlet, but I am interested in testing that somehow. I just need to figure out exactly what kind of tools I need for European standards. The light switch on the wall is a basic toggle switch, and I can hear a faint sound of sparks coming from the switch if I flick the switch very slowly near the point of connection. I guess that is hard to avoid, and I cannot say it clearly makes any difference when it comes to the weird stuff happening to my computer.

FYI, the house was built about 5 years ago.

Regarding line conditioning, I saw some equipment like Monster Core Power 800 USB (surge protector) which is supposed to reduce EMI and RFI, but I guess that is not enough for my use case.

...

I can try that. I need to find a long cable first!

 

[UsandThem]

I can try that. I need to buy a long cable first!

You can't carry your PC to a different room in the house, and plug it into a different outlet?

 

[skdayo]

You can't carry your PC to a different room in the house, and plug it into a different outlet?

Luckily, I found a long cable (no need to buy)! My computer setup is just meant to be long-term which makes it a bit inconvenient to set up again after tearing it down (a.k.a. as laziness). I think I should do that instead (maybe a long cable makes a difference), and I definitely must if nobody else can flick the switch for me.

 

[Flapdrol1337]

I used to have the same, plugged in a lamp and I'd hear the usb connected sound play.