Re : Whining PSU

[Guest]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

scotoma (me@play.co.uk) wrote in
message <ZVJuc.13872$Dm2.8753@front-1.news.blueyonder.co.uk>
Subject: Whining PSU

> what makes the capacitors on a PSU whine?

> The whining PSU is a new Mercury 300W powering a
> Gigabyte KT400 mobo, 40GB Samsung ATA100, AthlonXP
> 3000 "in a box" with supplied fan, 512MB DDR333,
> nVidia Riva TNT2 M64 (lol), 1x case fan, 52x CDRom,
> onboard sound, usb2 x 4. OS is windows XP Pro.
>
> I've tried changing the new 300W PSU with an old and
> known to be quiet same brand Mercury 300W PSU which used
> to silently power a Chaintech Apogee mobo, AthlonXP 1800,
> dual fan, 512MB DDR266, nVidia FX5200 128MB, 1x case fan,
> 200GB Maxtor ATA133, Pioneer 107, Plextor 48a, Yamaha SW1000XG
> sound card, SBLive 5.1 sound card and 6x usb.
> Surely the AthlonXP 1800 system (300W PSU) was drawing more
> power than the AthlonXP 3000 system yet the PSU's are
> squeeling like **** on the AthlonXP 3000 system????

Capacitors rarely whine noticeably, but bad capacitors can make coils,
including transformers, whine by causing the voltage regulation to
overcompensate. The power supply generates high frequency AC whose
duty cycle (amount of time it's on verses off) is varied to vary the
output voltage, but when capacitors are bad or the power supply is
simply overloaded, the regulation makes the duty cycle go too high,
causing very narrow pulses to be fed to the transformer and cause it
to whine. Since these are Mercury brand supplies, probably by Deer,
one of the worst manufacturers, and are rated for only 300W and you
have an XP3000+, I suspect they were simply overloaded, especially
their +5V and +3.3V outputs (the KT400 uses +5V to run the CPU). You
can't automatically assume that an XP1800+ system with an FX5200 draws
more power than an XP3000+ with a TNT2 M64, and most 300W power
supplies can't run an XP3000+. Think of getting a supply made by
Fortron-Source, such as those sold by www.directron.com or
www.newegg.com under several different brands. They're very good but
unusually inexpensive, and a 350W model should be able to run almost
anything.

 

[scotoma]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

"do_not_spam_me" <do_not_spam_me@my-deja.com> wrote in message
news:101710fa.0405311556.53393be8@posting.google.com...
> scotoma (me@play.co.uk) wrote in
> message <ZVJuc.13872$Dm2.8753@front-1.news.blueyonder.co.uk>
> Subject: Whining PSU
>
> > what makes the capacitors on a PSU whine?
>
> > The whining PSU is a new Mercury 300W powering a
> > Gigabyte KT400 mobo, 40GB Samsung ATA100, AthlonXP
> > 3000 "in a box" with supplied fan, 512MB DDR333,
> > nVidia Riva TNT2 M64 (lol), 1x case fan, 52x CDRom,
> > onboard sound, usb2 x 4. OS is windows XP Pro.
> >
> > I've tried changing the new 300W PSU with an old and
> > known to be quiet same brand Mercury 300W PSU which used
> > to silently power a Chaintech Apogee mobo, AthlonXP 1800,
> > dual fan, 512MB DDR266, nVidia FX5200 128MB, 1x case fan,
> > 200GB Maxtor ATA133, Pioneer 107, Plextor 48a, Yamaha SW1000XG
> > sound card, SBLive 5.1 sound card and 6x usb.
> > Surely the AthlonXP 1800 system (300W PSU) was drawing more
> > power than the AthlonXP 3000 system yet the PSU's are
> > squeeling like **** on the AthlonXP 3000 system????
>
> Capacitors rarely whine noticeably, but bad capacitors can make coils,
> including transformers, whine by causing the voltage regulation to
> overcompensate. The power supply generates high frequency AC whose
> duty cycle (amount of time it's on verses off) is varied to vary the
> output voltage, but when capacitors are bad or the power supply is
> simply overloaded, the regulation makes the duty cycle go too high,
> causing very narrow pulses to be fed to the transformer and cause it
> to whine. Since these are Mercury brand supplies, probably by Deer,
> one of the worst manufacturers, and are rated for only 300W and you
> have an XP3000+, I suspect they were simply overloaded, especially
> their +5V and +3.3V outputs (the KT400 uses +5V to run the CPU). You
> can't automatically assume that an XP1800+ system with an FX5200 draws
> more power than an XP3000+ with a TNT2 M64, and most 300W power
> supplies can't run an XP3000+. Think of getting a supply made by
> Fortron-Source, such as those sold by www.directron.com or
> www.newegg.com under several different brands. They're very good but
> unusually inexpensive, and a 350W model should be able to run almost
> anything.

Hi do_not_spam_me

Thank you very much for your reply. )
I'll replace the PSU as suggested.
Thanks again

Scotoma

 

[Guest]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

Mike Kay <mpk@nospamsanger.ac.uk> said:

> surely any product sold should work as advertised otherwise it shouldnt
> be on the market.

The specs on electronics are usually overblown. (e.g. horsepower of a
tablesaw, watts per channel of a car stereo, life of a coppertop). Quality
brands usually have ratings that are closer to reality, in a few rare
instances, they best brands may even have realistic ratings. That isn't
saying that they are all liars, they are extreme optimists.
--
Mac Cool

 

[Guest]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

In <cw4vc.105$wd7.95@front-1.news.blueyonder.co.uk>,
Mr Bill Payer <me@play.co.uk> wrote:

> I'll get a quality power supply to make sure that's the problem. If it still
> whines then the mobo's getting swapped to check it's not overloading the
> psu's.
>
> Can motherboards emit high frequency noise?

Yes, the coils can whine, and also some of those tiny srface mounted
components. If it's making the same noise with 2 PSUs it's much more
likely to be coming from the motherboard IMO. I've got an Asus which has
been doing it under load for over a year with no other ill effects
except that it's annoying. I had a noisy Intel cooler on it at first so
by the time I noticed the other noise I'd got rid of the board and CPU
it had replaced so it was too much hassle to RMA it :-(.

--
The address in the Reply-To is genuine and should not be edited.
See <http://www.realh.co.uk/contact.html> for more reliable contact addresses.

 

[Guest]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

Mike Kay <mpk@nospamsanger.ac.uk> wrote:

>> The only half decent analogy i can think of is when you buy a car that does
>> x miles/gallon. It doesnt mean you will actually get that efficiency all the
>> time. It means that is the best feasible value in the correct conditions.
>> Manufacturers are always fiddling with numbers to make their product appear
>> as great as possible

>a fair point, however continuning that analogy, you may accept that the
>stats may be slightly off, however the bottom line is that the car WILL
>still travel in a safe & reasonably reliable manner. surely if a psu is
>unable to supply the correct voltage then it is unfit for its purpose

The point is that total power output is almost academic; what matters
is the power on each of the 5V and 12V rails. Seemingly similar
supplies, with the same total output rating, will vary hugely.

As we seem to be using car analogies, it's similar to measuring the
performance of a car based on the size of it's tyres. It may give
some indication (faster more powerful cars tend to have wider low
profile tyres) but there's nothing to stop anyone sticking huge fatboy
racer tyres on a 1.1l shopping wagon. Indeed, if tyre size became the
de facto standard for measuring performance it would be pretty much
certain that's exactly what every manufacturer *would*. It is
precisely what has happened to many computer components, including
PSUs, where an almost irrelevant method of measuring comparative
performance has been adopted.

What's the quality of the design, construction and components used
will greatly affect the reliability of the unit. A low quality PSU is
far more likely to surge or dip under load, or fail completely in a
way which can do permanent damage to the delicate electronic
components it is supplying.

You might arguably take the risk with a budget build costing a few
hundred quid, where a £60+ PSU would add significantly to the cost of
the machine, but it seems ludicrous to me that people are equally
inclined to risk reliability or even damage to components worth many
hundreds of pounds for the sake of saving £20 or so against a total
cost of a grand or more. The amount you spend on a power supply
should be a proportion of the total machine cost; I'd consider 5% or
even approaching 10% of the total budget to be reasonable.

Coming back to our car scenario; you probably wouldn't bother fitting
a clapped out Fiesta with Ferrodo air cooled brakes and Continental
ContiSportContact 2 tyres but sticking a cheap PSU into a high spec
machine is something akin to driving a Porsche with cracked
second-hand brake disks and remould tyres!

--
>iv< Paul >iv<

 

[scotoma]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

"Tony Houghton" <this.address.is.fake@realh.co.uk> wrote in message
news:slrncbpmcu.a2i.this.address.is.fake@realh.co.uk...
> In <cw4vc.105$wd7.95@front-1.news.blueyonder.co.uk>,
> Mr Bill Payer <me@play.co.uk> wrote:
>
> > I'll get a quality power supply to make sure that's the problem. If it
still
> > whines then the mobo's getting swapped to check it's not overloading the
> > psu's.
> >
> > Can motherboards emit high frequency noise?
>
> Yes, the coils can whine, and also some of those tiny srface mounted
> components. If it's making the same noise with 2 PSUs it's much more
> likely to be coming from the motherboard IMO. I've got an Asus which has
> been doing it under load for over a year with no other ill effects
> except that it's annoying. I had a noisy Intel cooler on it at first so
> by the time I noticed the other noise I'd got rid of the board and CPU
> it had replaced so it was too much hassle to RMA it :-(.
>
> --
> The address in the Reply-To is genuine and should not be edited.
> See <http://www.realh.co.uk/contact.html> for more reliable contact
addresses.

Hi Tony Houghton

Thanks for your reply
I bought the Gigabyte mobo (£40uk) localy so I'll be giving the store a
visit quite soon.
Cheers again

Scotoma

 

[Guest]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

Paul Hopwood wrote:
> Mike Kay <mpk@nospamsanger.ac.uk> wrote:
>
>
>>>The only half decent analogy i can think of is when you buy a car that does
>>>x miles/gallon. It doesnt mean you will actually get that efficiency all the
>>>time. It means that is the best feasible value in the correct conditions.
>>>Manufacturers are always fiddling with numbers to make their product appear
>>>as great as possible
>
>
>>a fair point, however continuning that analogy, you may accept that the
>>stats may be slightly off, however the bottom line is that the car WILL
>>still travel in a safe & reasonably reliable manner. surely if a psu is
>>unable to supply the correct voltage then it is unfit for its purpose
>
>
> The point is that total power output is almost academic; what matters
> is the power on each of the 5V and 12V rails. Seemingly similar
> supplies, with the same total output rating, will vary hugely.
>
> As we seem to be using car analogies, it's similar to measuring the
> performance of a car based on the size of it's tyres. It may give
> some indication (faster more powerful cars tend to have wider low
> profile tyres) but there's nothing to stop anyone sticking huge fatboy
> racer tyres on a 1.1l shopping wagon. Indeed, if tyre size became the
> de facto standard for measuring performance it would be pretty much
> certain that's exactly what every manufacturer *would*. It is
> precisely what has happened to many computer components, including
> PSUs, where an almost irrelevant method of measuring comparative
> performance has been adopted.
>
> What's the quality of the design, construction and components used
> will greatly affect the reliability of the unit. A low quality PSU is
> far more likely to surge or dip under load, or fail completely in a
> way which can do permanent damage to the delicate electronic
> components it is supplying.
>
> You might arguably take the risk with a budget build costing a few
> hundred quid, where a £60+ PSU would add significantly to the cost of
> the machine, but it seems ludicrous to me that people are equally
> inclined to risk reliability or even damage to components worth many
> hundreds of pounds for the sake of saving £20 or so against a total
> cost of a grand or more. The amount you spend on a power supply
> should be a proportion of the total machine cost; I'd consider 5% or
> even approaching 10% of the total budget to be reasonable.
>
> Coming back to our car scenario; you probably wouldn't bother fitting
> a clapped out Fiesta with Ferrodo air cooled brakes and Continental
> ContiSportContact 2 tyres but sticking a cheap PSU into a high spec
> machine is something akin to driving a Porsche with cracked
> second-hand brake disks and remould tyres!
>

good point well made i guess!.

 

[Guest]

Archived from groups: uk.comp.homebuilt,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.homebuilt (More info?)

"Mr Bill Payer" <me@play.co.uk> wrote in message
news:cw4vc.105$wd7.95@front-1.news.blueyonder.co.uk...

> I'll get a quality power supply to make sure that's the problem. If it
still
> whines then the mobo's getting swapped to check it's not overloading the
> psu's.
>
> Can motherboards emit high frequency noise?

Yes. And then they squeak and chirrup, accompanied by whistles. And then
they die.

That's what happened to me anyway, as my caps were faulty (and one was the
wrong way round!). Got it fixed for the sake of it, it's now lovely and
quiet