Interference noise coming from inside PC enclosure

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LTK
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Interference noise coming from inside PC enclosure

Postby LTK » Mon Mar 28, 2011 4:05 pm UTC

Dear help desk, I've recently put toghether a new desktop PC, and I've had some noise issues with it. A lot of things are too loud for my liking, including the hard drives, PSU, and CPU fan, but the reason I'm asking for help is a sound that doesn't fall under any of those categories. It sounds a lot like radio interference; my dad's computer has the same sort of noise coming from his speaker towers, but in my case it's coming from inside the enclosure. And the weird thing is, it's only there when I'm browsing the internet, and then only when Flash is or has been active. Google Chrome sets it off right at startup, but Firefox doesn't get it until I open a page has a Youtube video embedded. Closing the tab or going to another page won't get rid of it, but closing the browser will. In addition, the noise stops when a page is loading, or when it is scrolling.

Now, if this is indeed radio interference, I thought it might come from the motherboard speaker, so I went and disabled 'Beep' in the device manager on Win7, but this didn't do anything. I was thinking of disconnecting the speaker on the motherboard itself, but I don't even know for sure if that's the source of the sound. Does anyone know what else I can do about this?

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Yakk
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Re: Interference noise coming from inside PC enclosure

Postby Yakk » Mon Mar 28, 2011 4:10 pm UTC

So, it sounds like static?

Finding the source of the sound will probably consist of detaching things that make sound...

Is your computer property grounded by any chance? You can pick up little 10$ plug analyzers to find out. Note that secondary grounding channels (like cable internet) can confuse this (even though they aren't up to par, ground-wise), so unplug everything else from the receptacle when you do the test.
One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision - BR

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LTK
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Re: Interference noise coming from inside PC enclosure

Postby LTK » Mon Mar 28, 2011 5:38 pm UTC

The noise is similar to static, but it doesn't sound random. It changes according to what I'm doing in the browser. Also, the power supply is plugged into a grounded outlet, so that ought to be covered.

I stuck my head inside the case once more, and if I can trust my own ears it appears that the noise is actually being made by the PSU. On one hand, that makes sense, considering I don't see a motherboard speaker anywhere. On the other hand, why does the power supply, of all things, produce static?

yewbie
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Re: Interference noise coming from inside PC enclosure

Postby yewbie » Mon Mar 28, 2011 6:49 pm UTC

There is a lengthy post about this on tomshardware dealing with this exact issue.

http://www.tomshardware.com/forum/254618-28-making-squealing-noise-mouse-scrolling-help

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Yakk
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Re: Interference noise coming from inside PC enclosure

Postby Yakk » Mon Mar 28, 2011 6:59 pm UTC

How do you know your plugs are properly grounded? (there being a 3rd hole tells you nothing)
One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision - BR

Last edited by JHVH on Fri Oct 23, 4004 BCE 6:17 pm, edited 6 times in total.

LTK
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Re: Interference noise coming from inside PC enclosure

Postby LTK » Mon Mar 28, 2011 7:58 pm UTC

yewbie wrote:There is a lengthy post about this on tomshardware dealing with this exact issue.

http://www.tomshardware.com/forum/254618-28-making-squealing-noise-mouse-scrolling-help

Well, nice to know that the problem is not uncommon, but there doesn't seem to be a definitive solution listed there. Some say it's a poorly manufactured PSU, some say it's because it uses too much power.

Yakk wrote:How do you know your plugs are properly grounded? (there being a 3rd hole tells you nothing)

I don't know about a third hole; these are Dutch outlets. But I do have a volt meter, and it measures about half a volt between the case and the zero outlet, same as the grounded clips. But I guess that's no longer relevant when the problem is in the PSU. It's looking like replacement is the only option.

yewbie
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Re: Interference noise coming from inside PC enclosure

Postby yewbie » Mon Mar 28, 2011 8:05 pm UTC

Some in that thread say disabling C1E support in your bios solves the issues too.

Power management - causing strange problems since windows 95.

LTK
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Re: Interference noise coming from inside PC enclosure

Postby LTK » Tue Mar 29, 2011 1:45 pm UTC

Yes, I noticed, but I don't actually know what it means. I'll look into that.

Edit: Found the option, disabled it, didn't help.


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