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Noisy power supply..

by radean / October 6, 2004 5:08 AM PDT

Getting a very irritating fairly low pitched hum from the computer. I temporarily stopped the Power supply fan, then the cpu fan, and made no difference. Reasonably sure it is not the HDD.
Actually the noise comes and goes a bit, and changes pitch slightly sometimes.
So question is, can a supply cause this kind of noise, even if the fan is not the problem?

Running XP with a 2 Gig P4 , 512M ram, 100Gig HDD, floppy, DVD drive, and CDRW drive. Power supply is only 300 watts, but have had no problems for 2 years, except this recent annoying noise. Motherboard caps all "appear" ok.

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The power supplies are switching types]
by Ray Harinec / October 6, 2004 6:07 AM PDT
In reply to: Noisy power supply..

usually have a transformer on the input. They can start to sing after a while. Many of the capacitors inside the supply are the same as the mobo leakers. If some of them are bad, the power supply voltages could lose some regulating capability and let some of the load noise through. Kinda WAG.

Have even heard video card singing. There is no dangerous voltages in an ATX case, so [ground yourself first] and touch any touchable things to see if the ringing stops.

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Thanks old timer..
by radean / October 6, 2004 7:16 AM PDT

Already tried touching this, and squeezing that, so maybe not a resonance.
Know a tad about switching power supplies from my old days in TV engineering work. Suppose if a core, or winding came loose, could cause some irritating noises.
Anyway, went and ordered a power supply from xPCgear. 450 watt job, for only $32.00 total with shipping. Sounds too cheap to really be of high quality, but if my current 300 watter works, then the new one should just cruise right along.
Appreciate the reply, and will let you know if problem is solved after I get the new supply.

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As you know that is great rationale when buying
by Ray Harinec / October 6, 2004 7:38 AM PDT
In reply to: Thanks old timer..

low price power supplies.

Really, be sure to let us know if that solves the problem. It would almost have to be a subharmonic of the switcher frequency and, as you say, a resonance somewhere.

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Re: Noisy power supply..
by Willy / October 6, 2004 2:10 PM PDT
In reply to: Noisy power supply..

Are those *all* the fans? Look for a case fan or a video fan, even a bridgeset fan. Plus, a failing fan doesn't necessary has to be 100% failure, still running to cause a noise and what you describe is a fan that comes and goes before it seizes. I exclude the power supply as mentioned by the other poster, if it takes another one to fix, go for it and get a larger wattage unit too.

good luck -----Willy Happy

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