SOLVED System unit hum (fan cleaned)

[Gwynny Pyg]

Hey people. My system unit makes a constant humming sound, always in a kind of pulsing in and out way. The volume varies but it's usually quite audible. I thought it must be the fan so I opened it up and cleaned the fan with compressed air and also cleaned out all the dust in the unit. But the problem remains. Any guesses or suggestions welcome. Thanks

 

[bassfisher6522]

Check all your hardware and cable connections.....make sure they are firmly seated, especially the external speakers.

 

[Grizzly]

Do you hear the sound only when running your OS or already at startup??

Although you clean the fan(s) already, it does not mean the fan is not defective. If you hear it at startup already, try stopping the fan (if it is the CPU fan, your PC will most likely shut down. that is why I recommended checking it at start up). If sound persists, its not the fan.
However, you may have a Fan on your video card as well which can cause that issue.

try to find out where the sound comes from in your computer (if it is a hardware issue).

 

[Trouble]

I thought it must be the fan so I opened it up and cleaned the fan with compressed air and also cleaned out all the dust in the unit. But the problem remains.

I've seen people "clean the fan" which can include the case fans as well as the CPU and GPU cooler, while ignoring the fan in the Power Supply, so....
Just checking to confirm that your thorough cleaning included the Power Supply fan.

 

[Gwynny Pyg]

Do you hear the sound only when running your OS or already at startup??

Although you clean the fan(s) already, it does not mean the fan is not defective. If you hear it at startup already, try stopping the fan (if it is the CPU fan, your PC will most likely shut down. that is why I recommended checking it at start up). If sound persists, its not the fan.
However, you may have a Fan on your video card as well which can cause that issue.

try to find out where the sound comes from in your computer (if it is a hardware issue).

At startup and it turned out to be the GPU fan. Thank you.

 

[Gwynny Pyg]

It was the GPU fan so I replaced that and it's all good. Thanks guys.

 

[BudVitoff]

What's a "GPU" fan?

 

[Trouble]

What's a "GPU" fan?

That would be the fan or fans on your video card.
Not all computers have separate, discreet add-in cards installed
AND
Even some that do may employ passive cooling with just a heatsink.
BUT
Generally higher performance video cards employ active cooling and have one fan or more on them.