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High Pitched, Low Volume Whine on PSU


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I recently aquired an Antec SmartPower 2.0 450W Power Supply. Although the power supply does work, it makes a very high pitched, low volume whine and the outer fan will not work.

 

I removed the supposed bad fan and when plugged in to the motherboard, it works fine, just not when it's in the power supply itself.

 

Looking closely at the board and caps, I did find a 2200uF 10v cap that was slightly domed, so I removed it and looking closely, it's broken open very slightly on the top as well. I have a new one coming.

 

The power supply does still work without it (very brief power on/of just to test) and the whine is still there, so it must be something else.

 

What would normally cause this whining? The power supply works fine either way, but I'd like to know just in case something is ready to go.

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Very unlikely to be a capacitor! ;)

 

Most likely it is one of the coils or even the switching transformer windings resonating/vibrating. I once read a very amusing review over at newegg about a power supply that was very tidy inside because it didn't have lumps of "glue" dripped everywhere like others he/she had seen. Power supply manufacturers quite often use this "glue" on coils and transformers to stop them vibrating at the switching frequency and its harmonics. Many power supplies make a high pitched whine that is often only audible to the younger generation because the frequency is at or beyond 20kHz. It often doesn't mean there's a problem, it just happens sometimes. Graphic card whine is more often than not the inductors in the power supply switching circuit and can sometimes be stopped with the application of clear nail varnish if they aren't of the fully enclosed variety.

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Very unlikely to be a capacitor! ;)

 

Most likely it is one of the coils or even the switching transformer windings resonating/vibrating. I once read a very amusing review over at newegg about a power supply that was very tidy inside because it didn't have lumps of "glue" dripped everywhere like others he/she had seen. Power supply manufacturers quite often use this "glue" on coils and transformers to stop them vibrating at the switching frequency and its harmonics. Many power supplies make a high pitched whine that is often only audible to the younger generation because the frequency is at or beyond 20kHz. It often doesn't mean there's a problem, it just happens sometimes. Graphic card whine is more often than not the inductors in the power supply switching circuit and can sometimes be stopped with the application of clear nail varnish if they aren't of the fully enclosed variety.

 

 

10-4... I Copy... Get out the Elmers :lol:

 

 

I'm replacing the domed 2200uF 10v capacitor just to be safe because it did have a very small crack in it anyway.

 

What kind of "glue" do you think they would have used? Silicone? Maybe even a hot glue gun type glue may work?

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  • 2 weeks later...

Antec Power Supplies are garbage!!

I have had 5 of them die, and all of them where making that high pitch whine. Even the RMA replacement Antec sent me has started to make noise this week.

From now on I will only buy Seasonic or Corsair PSU's

 

Reason for failure:

There are these tiny coils called inductors that resist rapid changes in current by creating an opposing force. It is called EMF and CEMF. Counter electromotive force is induced naturally in a collapsing current field in power supplies. So if it's a low frequency buzzing that's happening it is probably due to a part called the 'passive' power factor correction inductor or ppfci. This component is just a simple inductor with a core in it that is tunable. If the core is magnetized (usual core constituent composition is ferrite alloys) then it acts like a solenoid with a stuck core and vibration ensues.

If however, the sound coming out of it has a purely tonal aspect then it is much more likely that subharmonic counterparts of the feedback circuitry signal is feeding vibration into the inductors or coils and creating the tonal aspect of audible dissonance. In other words vrm's or voltage regulator modules can cause this issue through internal failure (feeding back an oscillating subharmonic in the 18hz to 20,000 Hz range of hearing).

If there is no load on the thing, it can even creating low level reflected waves which are absorbed back into the output stage through feedback loops in the circuitry and amplifying and generating the tone.

So why does it just begin to happen after it was fine for years? Lots of reasons. The coil windings are usually glued or taped down, heat generated in normal operation can loosen the glue or tape, thus letting the windings vibrate on the coil. Also the fit for the inductors ferrite core screw may not be an exact factory fit, and repeated phases of heating and cooling can expand metals and overtime generally loosen the cores screw tracking threads, much like a crack enlarges on the road due to heating and cooling.

Sometimes electrolytic capacitors start to leak, as the dielectric juice leaks out, an actual arcing of electricity can occur between plates producing a buzzing noise. Further other types of capacitors may do the same thing. for example ceramic capacitors can actually suffer the same heat/cool exposure, which eventually loosens one of the plates internally enough so that it can vibrate loose and express it's high frequency charge/discharge cycle through rapid internal plate oscillation, thereby transforming the electrical harmonics into a mechanical vibration which we hear as an audible buzz.

Edited by burned

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I replaced the 2200uF 10v cap that was domed and had a crack in the top today and the whine is completely gone now. The power supply was hooked to a desk/box build and fired up without a problem. That cap must have been connected to something else in the PSU that was whining because the cap was blown. All good now :thumbsup:

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Antec Power Supplies are garbage!!

I have had 5 of them die, and all of them where making that high pitch whine. Even the RMA replacement Antec sent me has started to make noise this week.

From now on I will only buy Seasonic or Corsair PSU's

 

2nd'ing this. My smart power was did the same thing. Its replacement suddenly stopped working. I wont buy from them again.

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