Weird buzzing from PC

Deskchair

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Oct 12, 2012
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Hello everyone!

I hope this is somewhat right forum category.

Sometimes my PC makes a weird buzzing sound right after i turn it on. It is not always - some 20-30% of the times. I have had experience with wire touching a fan, but i check inside the case and it cannot be the problem. From what i can tell buzzing most likely come form PSU.

It happens ONLY on startup. It last 1 min max. When i have logged into Windows it is gone, sometimes even before Windows loading screen starts. I have not had any noticeable problems (crashes, restarts, error messages).

So it doesn't really bother me much, but i am worried it might affect my PC in long term.
 

trigg

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Nov 20, 2012
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Could be just vibrations? Does it stop if you give it a slight bang or apply pressure to the case area where the noise is coming from (don't touch any circuitry!) ?
 

Deskchair

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Oct 12, 2012
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Will have to try it next time i hear it. :) Is there something that works differently (mechanically) during the boot-up? As i said it NEVER makes the sound after startup.
 

ttcboy

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Jul 14, 2006
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If none of the cable is touching the fan, most likely it's the fan bearing problem.

Do u hear the same noise under heavy system load as well like gaming? If so, it might be ur graphic card fan problem coz some fan on graphic card tend to blast full speed at the system start up and slows down after a while (my old rig's GTS 240 does that).

One way to find out is to open up the side panel and try to listen which parts are emitting the sound without touching any internal circuitry.
 

Deskchair

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Oct 12, 2012
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According to sound it comes from PSU. But it happens only on startup. It is silent even after 2 hours of Battlefield 3 on 1080p max settings. I don't really feel like opening PSU since i think it will void the warranty.
 

ttcboy

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Jul 14, 2006
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I came across some posts about hearing the rubber screeching sounds from the case before and some people commented that it might be from PSU but it only applicable to fanless PSU where the sound come from some thermal contacts.

Please don't try to touch any part of PSU internal parts coz it will not only void ur warranty but also might give u serious injury.

15years ago when the prices of PSU are not that cheap, I've tried to repair it myself since the warranty is over. Happens that one of the capacitor (big one) is faulty and unable to refresh the stored electricity. Luckily, i just get away with a minor burn. I was tracing the circuit with multimeter and my finger accidentally shorted the faulty capacitor terminals and it discharged.