Whistling PSU

[Tom41]

You may remember I posted some time ago about the Kobian Mercury PSU failing due to bad caps. I replaced it with a new PSU, a dual-fan unit. Looking through the vents, I saw it was packed with Teapos.

Now, the PSU has started making a 'whistling' noise both when powered up and on standby. The noise appears to be coming from the PSU itself, and if I flip the isolator switch the whistle drops in pitch and then stops.

I've had another look through the vents and can't see any sign of caps bulging or venting. I wonder if the Teapos have failed without physical signs, like they're notorious for doing?

Note: The PC is still stable; no sign of random reboots or memory errors yet.

[shadow]

Re: Whistling PSU

I have heard that some caps can whistle, however it is much more common with inductors.

Vibration is the cause of whistling and most of the time glue is put over the inductors and some capacitors to stop the vibration.

Chances are that it is nothing to be worried about, if you want to eliminate it, you can add some more glue to the component that is producing the whistling noise.

[i4004]

Re: Whistling PSU

caps don't whistle...as shadow said look for shaky inductors and trafos...if it bothers you.

[Fizzycapola]

Re: Whistling PSU

Loose labeling can become like a speaker too. I read Corsair PSU tech support people returning PSU because of noise, Corsair stuck the label back down for them. Mine also had a shaky label, but I used paper glue instead of returning it, hope warranty wasn't invalidated.

Edit: though the fault was a buzzing noise, not a whistle.

[Tom41]

Re: Whistling PSU

I just opened up the PSU and had a look, now that I know it's out of warranty. Three of the Teapo caps on the output side have bulged, and one has exuded a tiny amount of electrolyte.

Looks like I caught it just in time - while the system was still stable, the PSU may have smoked at any time and taken the whole PC with it! Now got a new PSU, how long will that last?

Edit: Oddly, this PSU doesn't seem to have any kind of PFC, either mounted to the case or on the main board!

I might take some pics of this PSU and post them in the Build Quality Pictorial thread when I get time.

[zandrax]

Re: Whistling PSU

@ Tom: I saw your previous psu in the "Pictorial build" thread: it's empty.
No filter caps, no X and Y caps, skinny heatsinks, likely overrated components: bad caps are the last of your problems, it is unsafe (and I think outlaw too) because it has no protections for your hardware and yourself. I hope your new one is decent.
Don't even try to repair it unless you have some used caps you want to throw into: it's junk.

Zandrax

[Junk Parts]

Re: Whistling PSU

The only thing I ever had that made strange noises was a cheap audio power booster. It was a burnt out trashcan item that a friend fixed up for me. A bunch of resistor had fried in it. Since he had no spec sheet for it he made a best guess on the values to replace them with. It kicked butt when he was done but with a small problem. What ever music was playing you could hear that same music eminating from the case of the Power booster too...LOL My guess is that the iron core inductors in it were acting like little speakers.