Question What is this sound coming from my power supply?

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sgnz

Commendable
Apr 19, 2019
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The sound isn't made by the MOSFETs. It's caused by the switching of the MOSFETs and the sound is the current pulsing through the magnetics (probably the inductor coil). They probably covered a bunch of components with caulk and it's fallen off or dried up or something.
So your saying the noise is the sound of the PWM activating as the mosfet is switching/ filtering the current and or voltage? The noise kind of sounds like a capacitor (a mosfet can sometimes be a capacitor?) which as you will know can store a charge during the AC wavelength when unused then use the stored power when the sine wave supplies less than your appliances prescribed voltage.

This brings me to my above post about some electrical work being carried out and the issues OP is facing. If the power supplying the PC is poor ie earth leakage or lack of earthing then maybe that could cause the components in the psu to struggle maybe causing the noise? And if this is the case the psu could potentially fail and take other parts in the PC out with it. I could be over exaggerating usually its poor electrical devices that trip the circuit protection before an issue can occur. But since im from new zealand and have no idea which country OP is from it could be possible. I have heard the states do have issues with their power delivery thats why alot of you folks have UPS protecting your PC's etc

I work as an electrician for an HVAC company I dont know alot about PCB's and their components. But a work colleague is a registered service technician so its quite good when we both go out to call outs together.
He knows the nitty gritty and i know the power delivery! Means we both get to learn!

Hope what I said wasnt completely wrong im still learning the component ins and outs :)
 
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Hallahawk665

Prominent
Jun 17, 2020
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First off did this only occur after the electrical work was completed? Can you explain more on what the electricians did? Im an electrician albeit im from New Zealand so our rules and regulations not to mention our power distribution network is potentially quite different. We use no nuclear. Mainly hydroelectric / and wind but some fossil fuels :/ If your having issues since electrical work has been carried out im pretty positive its something they have done negligently!
Just a wild guess are you from the states?
What safety mechanisms are you talking about?
Yes it occured after the electrical work was completed, but not RIGHT after. I guess this could be because it rained alot the last couple days and apparently the problem was with an underground cable that wasn't shielded properly so the water got in and messed with the electricity. The lightbulbs also flickered every now and then, but they wouldn't flicker every time I heard a noise from the computer's PSU. I'm from Romania btw, not the states and I'm not sure what safety mechanism they removed, I just know it had something to do with regulating the current (to not allow too much current into the house so electronics don't get fried). This is eastern europe after all so nobody here really cares about safety and regulations, they just drink and smoke all day xD
 
So your saying the noise is the sound of the PWM activating as the mosfet is switching/ filtering the current and or voltage?
No. I said the noise could be coming from the PFC coil. MOSFETs don't make audible noise, but create a lot of electrical noise.

The noise kind of sounds like a capacitor (a mosfet can sometimes be a capacitor?)
No. Only caps I've heard make noises are those in the process of venting and some X capacitors because the film can resonate with noise on the mains.

which as you will know can store a charge during the AC wavelength when unused then use the stored power when the sine wave supplies less than your appliances prescribed voltage.
Yes and no. The filtering caps filter noise from the PSU back to the mains. And a burst mode is introducing a lot of noise in both directions of the circuit.

This brings me to my above post about some electrical work being carried out and the issues OP is facing. If the power supplying the PC is poor ie earth leakage or lack of earthing then maybe that could cause the components in the psu to struggle maybe causing the noise?
No. Not "struggle" at least. Just make noise.

And if this is the case the psu could potentially fail and take other parts in the PC out with it.
No.

I could be over exaggerating usually its poor electrical devices that trip the circuit protection before an issue can occur.
Tripping the mains is the best thing that could happen... if that's what needs to happen.

But since im from new zealand and have no idea which country OP is from it could be possible. I have heard the states do have issues with their power delivery thats why alot of you folks have UPS protecting your PC's etc
Umm... What? You need a UPS when your mains goes out frequently. Like when PG&E does rolling black outs to prevent forest fires or FPL can't get the mains back up right away after a hurricane. Having someone that doesn't know what they're doing re-wire your house is not exclusive to North America.
 

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