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PSU internal component failing ?

  johndrew 10:03 22 Nov 2011

Or something else?

Recently when switching on the PC at the mains I have noticed a high pitched noise - not fan like, more like an oscillator whine. Additionally it takes a couple of seconds (noticeable time) before I can press the start button and get a green power light - this used to be instantaneous (almost) previously.

When turning the PC off (after Windows has closed) the whine is still present until mains power is turned off then it raises slightly in pitch and decreases to nothing (inaudible). I appears to me that it could be related to a capacitor discharging after power being removed.

The PC is functioning normally in other respects and the noise, assuming it is constantly present, is masked by fans/drives during operation. It is only when fans/drives are not on that I hear it.

Does anyone have any experience/knowledge of similar noises which may indicate a fault?

Many thanks in anticipation for any advice.

  johndrew 10:57 22 Nov 2011

Thanks for coming back.

The exact location is not clear; this is the problem. My hearing isn't what it was (some years ago) and although it sounds to be coming from the back of the PC, where the PSU is located, it is also close to other items on the motherboard.

I think I can rule out RAM and items close to the front though.

  johndrew 11:06 22 Nov 2011

Thanks bjh.

I accept the PSU isn't one of the best in the world, it's a Hiper 480W unit, but given that I am looking to replace the PC (probably after Christmas) I was looking for a bit of confidence that a replacement PSU or something else wasn't on the cards in the very near future.

If it is capacitor whine am I likely to see a sudden failure?

  johndrew 11:09 22 Nov 2011


No mic, but I have paper.

I shall try that. A bit of plastic tube didn't work but the paper tube diameter can be controlled better.

  johndrew 10:36 23 Nov 2011

Sorry to have been so long in coming back with any results but it took some time to do as was suggested.

With only power on to the PSU but with all other parts normally connected I used various items from rolled paper to plastic pipe as a stethoscope facility. The whine is definitely to the rear (my wife also agrees this) and I have a level of confidence that it is from the PSU.

I did move my hearing trumpets around to see if I could get a definite difference top to bottom of the case but it was difficult to gain straight access vertically - the noise seems to be projected downward from the bottom (fan grill area) of the PSU.

Can anyone now give a better idea as to my question, please. Specifically, if it is capacitor whine am I likely to see a sudden failure?

  spuds 11:26 23 Nov 2011

When you usually get 'whines/noises' it possibly means fan's, hard-drive or PSU.

When its appears to be a suspect PSU problem, after using sound testing, PSU testers etc (which only tells you the item is working or not), I spend about £14/£16 on a replacement PSU unit. Some people might have their own opinions on the cheaper PSU, but I have never had a problem with them.

  johndrew 11:41 23 Nov 2011

Many thanks for the information all.

I shall let sleeping dogs lay for the moment and hope I don't need the extra expense.

I like the video on PSUs - though for some reason there is no sound. I did check mute, volume and my speakers but ....

As an aside I put the PC into standby for a while and there was no whine. All a bit strange!!

  spuds 12:34 23 Nov 2011


Hate to say this, and I hope that I am wrong. But when that happens to a PSU, (from my past experience) it could well be an indicator of a possible imminent sudden failure?.

If you have any important things on the computer that you want to save, get them backed up pronto.

  Bris 19:28 23 Nov 2011

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