high pitched noise from computer psu

[Peter]

ATX computer power supply.
Rated at 450 watts
(that's a joke!)
Made in China.
works but makes a high pitched noise.
Must be oscillating somewhere. Most likely cause?
Faulty transistors? or more likely bad filter caps?
On input to switching transistors or on the low voltage side?

I'm looking for tips.
thanks

Peter

 

[Jerry G.]

This can commonly be from the switching driver transformer having some
internal loose windings, a decoupler cap(s) going defective, or something
mechanically resonating.

Most of the time, we found these supplies not worth to invest the time and
money in to, since they are very low in cost to replace.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Peter" <pmhughes@ozemail.com.au> wrote in message
news:qaHqb.78$744.4484@nnrp1.ozemail.com.au...
ATX computer power supply.
Rated at 450 watts
(that's a joke!)
Made in China.
works but makes a high pitched noise.
Must be oscillating somewhere. Most likely cause?
Faulty transistors? or more likely bad filter caps?
On input to switching transistors or on the low voltage side?

I'm looking for tips.
thanks

Peter

 

[CJT]

Peter wrote:

ATX computer power supply.
Rated at 450 watts
(that's a joke!)
Made in China.
works but makes a high pitched noise.
Must be oscillating somewhere. Most likely cause?
Faulty transistors? or more likely bad filter caps?
On input to switching transistors or on the low voltage side?

I'm looking for tips.
thanks

Peter

They have to oscillate. That's how they work. But they shouldn't
make audible HF noise. Check for loose screws or laminations on the
transformer(s).

--
After being targeted with gigabytes of trash by the "SWEN" worm, I have
concluded we must conceal our e-mail address. Our true address is the
mirror image of what you see before the "@" symbol. It's a shame such
steps are necessary. ...Charlie

 

[Mike Wilson]

Hi Pete
I know this might sound a little starnge, but it may be the fan in the power
suppy. I've had old power supplies that make a high pitched sound. I gave
them a little thump and the sound goes away. If this problem is the one I
just described it usually happens with a power supply that is a few years
old. You mentioned that it is a ATX power supply, the power supply is at the
top of the case, so if you give the case a little thump, not too hard, then
it should go away. If what you described isn't the fan, I can't help ya.
Cheers!!!


"Peter" <pmhughes@ozemail.com.au> wrote in message
news:qaHqb.78$744.4484@nnrp1.ozemail.com.au...

ATX computer power supply.
Rated at 450 watts
(that's a joke!)
Made in China.
works but makes a high pitched noise.
Must be oscillating somewhere. Most likely cause?
Faulty transistors? or more likely bad filter caps?
On input to switching transistors or on the low voltage side?

I'm looking for tips.
thanks

Peter

 

[CJT]

Mike Wilson wrote:

Hi Pete
I know this might sound a little starnge, but it may be the fan in the power
suppy. I've had old power supplies that make a high pitched sound. I gave
them a little thump and the sound goes away. If this problem is the one I
just described it usually happens with a power supply that is a few years
old. You mentioned that it is a ATX power supply, the power supply is at the
top of the case, so if you give the case a little thump, not too hard, then
it should go away. If what you described isn't the fan, I can't help ya.
Cheers!!!

It's certainly true that fans can squeal as they reach the end of their
life, especially the cheap sleeve type. Sometimes they load up with
dust, too.

"Peter" <pmhughes@ozemail.com.au> wrote in message
news:qaHqb.78$744.4484@nnrp1.ozemail.com.au...

ATX computer power supply.
Rated at 450 watts
(that's a joke!)
Made in China.
works but makes a high pitched noise.
Must be oscillating somewhere. Most likely cause?
Faulty transistors? or more likely bad filter caps?
On input to switching transistors or on the low voltage side?

I'm looking for tips.
thanks

Peter

--
After being targeted with gigabytes of trash by the "SWEN" worm, I have
concluded we must conceal our e-mail address. Our true address is the
mirror image of what you see before the "@" symbol. It's a shame such
steps are necessary. ...Charlie

 

[Bruce]

In Aussie, it would be cheaper to replace the power supply than open the old
one, maybe upgrade to a P4 then you will need a new PS, but a bit of lube
spray
on the fan nver hurt, I've seen PS blow up just because the fan locked up -
have fun
"Peter" <pmhughes@ozemail.com.au> wrote in message
news:qaHqb.78$744.4484@nnrp1.ozemail.com.au...

ATX computer power supply.
Rated at 450 watts
(that's a joke!)
Made in China.
works but makes a high pitched noise.
Must be oscillating somewhere. Most likely cause?
Faulty transistors? or more likely bad filter caps?
On input to switching transistors or on the low voltage side?

I'm looking for tips.
thanks

Peter