Power supply makes noise

[Sergio T.P.]

Hi all.

I've bought a new 400 W power suply. It was supposed to be a silence power
suply. In fact, it is less noisy than my old one, but when I turn on the
compueter it makes a lot of noise... It's not a regular noise, like the
noise of a fan. It's some kind of tickling sound... In 3 / 4 minutes it goes
lower untill it gets the normal level of noise of the power supply.
Sometimes the noise disappears when I lift a bit the case and let it down
again, or if I shake a bit the case...
Extrange thing is that I had exactly the same problem with my OLD power
supply... (high sound when switching on).

It that normal?? perhaps it sounds untill it warm up or something??

Sorry for my broken English.
Thanks

 

[q_q_anonymous]

Hi all.

I've bought a new 400 W power suply. It was supposed to be a silence power
suply. In fact, it is less noisy than my old one,

actually that is to be expected. Higher wattage is supposed to be less
noisy. The logic is that it can produce up to 400w because it is more
efficient in that it producese less heat, so has less heat to remove.
(so the fans needn't spin as fast).

Maybe if the 400w PSU was also operating at 400w then it could be as
loud as a 300w (operating at 300w). But I guess typically the 400w PSU
won't be using all 400w. Especially not in a computer that ran with a
300w.
If you require 300w , then I guess whether you put a 300w or a 500w or
a 700w PSU in there, you'll get 300w. 400w is better though, less
strain on the PSU in intensive times.

but when I turn on the
compueter it makes a lot of noise... It's not a regular noise, like the
noise of a fan. It's some kind of tickling sound... In 3 / 4 minutes it goes
lower untill it gets the normal level of noise of the power supply.
Sometimes the noise disappears when I lift a bit the case and let it down
again, or if I shake a bit the case...
Extrange thing is that I had exactly the same problem with my OLD power
supply... (high sound when switching on).

It that normal?? perhaps it sounds untill it warm up or something??

you have to narrow this down. It's important that you sort of found a
trigger. THe defeault position causes the noise. But lifting the case a
bit stops the noise.

try taking the power supply out of the case. If it makes a noise then,
it's easy to narrow down. If it doesn't make a noise, great. Put it
in the case, turn it on, see if there is a noise. If so, take it out,
or move it somehow, put it in a bit differently.

A friend had a similar problem, I think with the power supply. We
found that putting some tissue paper between the power supply and the
case stopped the noise. Maybe it secured it better and stopped the
vibrations.

Lifting the case is causing some other changes that are stopping the
noise. So you have to experiment with moving things, holding things,
not holding things, squeezing things. Move PSU from a position where
there is noise(screwed in case as it is currently), to a position where
there is no noise, finding the dfiferent ways. Move from a position of
no noise(e.g. psu out of case), gradually trying to secure the psu,
until yju suddenly find noise, then you've foudn a trigger. Hold it in
place with your hand in te air. Then against the case. Then with tissue
paper between it and the case, with screws in securing the PSU.

It's possible that there's something knocking the fan inside the PSU.
You could open the PSU and move any cable away from the fan. It could
be nothing to do with the PSU, it could be that a cable is wacking a
case fan.
Regarding opening the PSU
2 issues to take into account so as not to hurt yourself
* It must be unplugged. Then you won't get electricuted seriously. So
that big fear can blow away.

* That risk above was the big risk. The only risk now is not too bad.
It's the charge in the big capacitors, and you touching a big
capacitor. They , according to googling, will hurt your finger if you
touch them and give you a shock, but probably not much more. You might
want to wait for them to discharge. A day maybe to be safe, i'm not an
electrician. But if you just open it to check a cable - the fan cable
presumably, then you wouldn't be touching them. I think they're covered
by a metal thing anyway like a homeless shelter for capacitors.

And if you're really worried, use your right hand. so electricity
travels down your right side, missing your heart which is on the left
side.

 

[Rod Speed]

(e-mail address removed) wrote

Sergio T.P. wrote

actually that is to be expected.
Nope.

Higher wattage is supposed to be less noisy.
Nope.

The logic is that it can produce up to 400w because
it is more efficient in that it producese less heat, so has
less heat to remove. (so the fans needn't spin as fast).

Utterly mangled.

Maybe if the 400w PSU was also operating at 400w
then it could be as loud as a 300w (operating at 300w).

More utter mangling. If both supplys had the same efficiency, the
400W supply would have more power lost in the supply itself, so
with the same fans used, there is more heat to get rid of.

But I guess typically the 400w PSU won't be using all
400w. Especially not in a computer that ran with a 300w.

Yes, but it wont necessarily be any less efficient than the 300W
supply, so you should get about the same power lost in the supply.

If you require 300w , then I guess whether you put a
300w or a 500w or a 700w PSU in there, you'll get 300w.

Yes, you did manage to get that bit right.

400w is better though, less strain on the PSU in intensive times.

Utterly mangled all over again.

you have to narrow this down. It's important that you
sort of found a trigger. THe defeault position causes
the noise. But lifting the case a bit stops the noise.

Thats an absolutely classic example of case vibration, that lifting effect.

Presumably the case warms up enough to expand
whats a bit loose enough so it doesnt vibrate anymore.

It might also be a resonance effect with one of the variable speed
fans running a little faster once its warmed up so you dont see the
a resonance effect with the case once its warmed up a bit.

try taking the power supply out of the case. If it makes a noise
then, it's easy to narrow down. If it doesn't make a noise, great.
Put it in the case, turn it on, see if there is a noise. If so, take it
out, or move it somehow, put it in a bit differently.

Its unlikely to be the power supply given that he
gets that effect with two different power supplys.

A friend had a similar problem, I think with the power supply.
We found that putting some tissue paper between the power
supply and the case stopped the noise. Maybe it secured it
better and stopped the vibrations.

Lifting the case is causing some other changes that are stopping the
noise. So you have to experiment with moving things, holding things,
not holding things, squeezing things. Move PSU from a position where
there is noise(screwed in case as it is currently), to a position
where there is no noise, finding the dfiferent ways. Move from a
position of no noise(e.g. psu out of case), gradually trying to
secure the psu, until yju suddenly find noise, then you've foudn a
trigger. Hold it in place with your hand in te air. Then against the
case. Then with tissue paper between it and the case, with screws in
securing the PSU.

It's possible that there's something knocking the fan inside the PSU.

Nope, you wouldnt get that warmup effect with that and you
wouldnt get the same effect with two completely different PSUs.

You could open the PSU and move any cable away from the fan.
It could be nothing to do with the PSU, it could be that a cable is
wacking a case fan.
Regarding opening the PSU
2 issues to take into account so as not to hurt yourself
* It must be unplugged. Then you won't get electricuted
seriously. So that big fear can blow away.

* That risk above was the big risk. The only risk now is not too bad.
It's the charge in the big capacitors, and you touching a big
capacitor. They , according to googling, will hurt your finger if you
touch them and give you a shock, but probably not much more. You might
want to wait for them to discharge. A day maybe to be safe, i'm not an
electrician. But if you just open it to check a cable - the fan
cable presumably, then you wouldn't be touching them. I think they're
covered by a metal thing anyway like a homeless shelter for capacitors.

And if you're really worried, use your right hand. so electricity travels
down your right side, missing your heart which is on the left side.

Makes a lot more sense to not put your hands
inside the power supply with it plugged in.

 

[kony]

actually that is to be expected. Higher wattage is supposed to be less
noisy. The logic is that it can produce up to 400w because it is more
efficient in that it producese less heat, so has less heat to remove.
(so the fans needn't spin as fast).

Maybe if the 400w PSU was also operating at 400w then it could be as
loud as a 300w (operating at 300w). But I guess typically the 400w PSU
won't be using all 400w. Especially not in a computer that ran with a
300w.
If you require 300w , then I guess whether you put a 300w or a 500w or
a 700w PSU in there, you'll get 300w. 400w is better though, less
strain on the PSU in intensive times.

That's not necessarily true. Sure, there are some newer PSU
that are often in high wattage ratings like 400W, these
higher wattage PSU have become more common and due to the
recent 80-plus initiative there are "some" that are more
efficent. There are also plenty of 400W PSU that are no
more efficient than 300W models.

Generally speaking, since the newer 300W models can be more
efficient (than preceeding models) too, we can generally
discount the wattage and still assume the 400W produces
more heat, IF the system is using that much more power, a
roughly 4:3 ratio more if all else were equal (which I doubt
would be true, but this just corresponding to the wattage).

 

[q_q_anonymous]

(e-mail address removed) wrote


Utterly mangled.


More utter mangling. If both supplys had the same efficiency, the
400W supply would have more power lost in the supply itself, so
with the same fans used, there is more heat to get rid of.


Yes, but it wont necessarily be any less efficient than the 300W
supply, so you should get about the same power lost in the supply.


Yes, you did manage to get that bit right.


Utterly mangled all over again.

Alright.
I can't find the site that said that higher wattage was less noisy and
other things, but I can believe that it was wrong. Since I haven't read
it elsewhere and it wasn't a famous site or impressive site. And of
course Kony says it's wrong.

Thats an absolutely classic example of case vibration, that lifting effect.

Presumably the case warms up enough to expand
whats a bit loose enough so it doesnt vibrate anymore.

It might also be a resonance effect with one of the variable speed
fans running a little faster once its warmed up so you dont see the
a resonance effect with the case once its warmed up a bit.


Its unlikely to be the power supply given that he
gets that effect with two different power supplys.

yeah, but since this method involves taking the PSU out of the case
anyhow, and running the PSU out of the case, it's part of the process
of trying to put the PSU in without any vibrations. It's also good to
check all possibilities. Especially when it takes 0 seconds longer to
check it.

Nope, you wouldnt get that warmup effect with that and you
wouldnt get the same effect with two completely different PSUs.

That statement you just wrote is only relevant to the last sentence of
mine that you quoted.The rest of what I wrote deals with the vibration
possibility.

And to the possibility you like to attack - of it being the PSU, what I
already wrote in this post applies. i.e. he'll find out if it was the
PSU, in 0 seconds. If it is, then he'll have to cosndier opening up the
PSU.
It that possibility were to take time, or wasn't part of the more
likely, vibration check, then i'd have said "if vibration check
fails... try the following less likely possibility ...."

Makes a lot more sense to not put your hands
inside the power supply with it plugged in.

I said it must be unplugged - in the first risk - which was the main
risk.

Even when unplugged, you could still have the charge in the capacitors.
(second risk)

 

[Rod Speed]

(e-mail address removed) wrote

Rod Speed wrote

yeah, but since this method involves taking the PSU out of the
case anyhow, and running the PSU out of the case, it's part
of the process of trying to put the PSU in without any vibrations.

No evidence the the PSU has anything to do with the problem.

It's also good to check all possibilities.

He's done that by trying another power supply.

Especially when it takes 0 seconds longer to check it.

Complete waste of time when he has already tried a different power supply.

That statement you just wrote is only relevant
to the last sentence of mine that you quoted.

That is why I interleaved my comments,
so I can comment on particular bits of yours.

The rest of what I wrote deals with the vibration possibility.

Yes, and I didnt comment on those comments of yours about
the vibration, JUST pointed out that the problem wont be due
to something rubbing up against the fan in the PSU, because
that wont happen with two completely different PSUs.

And to the possibility you like to attack - of it being
the PSU, what I already wrote in this post applies.

No it doesnt, because he wont have got that
effect in two completely different PSUs, and
you dont see that lifting effect with a PSU either.

The vibration problem is elsewhere in the case

i.e. he'll find out if it was the PSU, in 0 seconds.

He's already found out by trying a different PSU.

If it is,

No possibility what so ever of it being that, because
he has already tried a completely different PSU.

then he'll have to cosndier opening up the PSU.

Taint gunna happen.

It that possibility were to take time, or wasn't part of the
more likely, vibration check, then i'd have said "if vibration
check fails... try the following less likely possibility ...."

Its completely pointless considering the PSU because he
has already tried a completely different PSU and has got
the same effect, the noise goes away once the system
warms up and he gets the lifting effect when its cold.

I said it must be unplugged - in the first risk - which was the main risk.

So there was no point in that last bit about using your right hand.

Even when unplugged, you could still have
the charge in the capacitors. (second risk)

Nope, they have bleed resistors across them.

 

[kony]

Nope, they have bleed resistors across them.

.... and the PSU contiues to runs the 5VSB and control
circuit after unplugged, which would drain off most of the
power even if the resistors weren't there.

 

[q_q_anonymous]

... and the PSU contiues to runs the 5VSB and control
circuit after unplugged, which would drain off most of the
power even if the resistors weren't there.

interesting, I hadn't thought about that, thanks.

 

[q_q_anonymous]

(e-mail address removed) wrote


No evidence the the PSU has anything to do with the problem.


He's done that by trying another power supply.


Complete waste of time when he has already tried a different power supply.

Running the PSU out of the case is a more sensible test, and it'll be
done anyway. I would use the results of that one, since we're
unavoidably doing it anyway.

In practice, there are times when one makes assumptions that are quite
reasonable to make, in narrowing down a problem, and then you hit a
wall, and on reevaluating it from scratch with a fresh mind, you
realise one of the assumptions is wrong. It is very rare that a fair
assumption proves wrong, but it happens sometimes.

In his case, there's a slight chance that both PSUs have the same
problem of rattling inside from the wire hitting the fan. And when he
lifts the case it moves that cable a bit. And there may be unforeseen
issues too that cause one to question assumptions. So i'm not going to
jump into assumptions. It's good to double check, and choose your
tests carefully. And when looking at possible problems,solutions and
tests, it's a good idea to double check, especially if a double check
takes 0 seconds(it being patr of another necessary check).

I'll give you one of the rare examples where I've made an assumption -
or rather assigned a wrong probability (since I am willing to revaluate
from scratch with a fresh mind ignoring assumptions. Since one is only
human. ).

I had 2 computers hooked up to a DSL router/modem. One of them, I
never had any problems with the internet connection. The other one,
the internet connection kept going from time to time, then coming back.
Every time, I checked the other computer, saw that it was fine. The
router configuration is ok, it hasn't been changed. There's no in built
firewall in the "router" misconfigured.
So I figured that the router is fine(working), since one of the
computers gets to the internet with it.
I tried plugging the "computer that worked" into different ports, and
it still worked. So that double checked that the router is fine, in all
ports. It was really looking like it was this one computer that was
the issue.
To narrow things down fast with that one computer, I booted knoppix,
and got no internet connection (usually i would). So, it wasn't a
broken software firewall on the computer blocking the connection.
I tried a cat5e cable from the working computer, and it worked in the
other one, but then I lost th einternet connection again. Put it back
in the working one and the working one was fine.
This was narrowing down to the NIC in that "computer that wasn't
working".
I replaced the NIC, and got net access for 5 minutes, then failure
again.

I started getting bothered, because I could continue testing this, but
it is not a good possibility , infact the only possibility that I could
think of, and the most likely, that - and this is strange - that the
computer was assassinating my NICs. Could be a bad PSU, could be a bad
MBRD.. I don't want to keep trying new NICs in that computer and
potentially having them assassinated.

So I quite looking at the problem. After about a week, the "working
computer" suddenly failed to get an internet connection through the
router!! Then I got suspicious that the router was at fault!
I had an old router which I had declared broken but left it in the
shelf incase it had any life in it after being left around for years,
in the desparate event that i'd have to bother trying to use it. It
worked for about an hour!! And gave all my comps internet access. So
I went out and bought some new working routers - with warranties , from
my ISP!

So there you see a good example. Everything pointed to the router
being fine. My checks and double checks that I described. (though I was
limited, not having another working router to try). It really looked
like the NIC.. But that turned out wrong.

What you are doing, is making assumptions absolute.
I might find myself saying "I find it hard to believe that this is the
problem..." or "this is most likely, this is unlikely". And I do rule
things out.. But not permanently. And in deciding tests and possible
solutions, I look at how much time they'll take. If it's a great test
and it takes 0 seconds, i'm all for it. And i'm not against doing it
twice to be sure!

That is why I interleaved my comments,
so I can comment on particular bits of yours.

the method is snippnig and interleave. It applied here.

Nope, they have bleed resistors across them.

And out of interest, were these 'bleed resistors' also on all old AT
power supplies and All ATX PSUs?

 

[q_q_anonymous]

I'll check how long my ATX(so, with 5VSB) takes to discharge. with a
multimeter on 5VSB.

According to this guy quoted below, 1000 seconds (16.6 minutes). Though
it seems he didn't take into account the 5VSB+control circuit that you
mention.
He also suggested that some may not have the restistors. And perhaps
some may have different rated resistors


http://forums.silentpcreview.com/viewtopic.php?t=3361&view=previous
larrymoencurly
"There are bleeder resistors across the big high voltage filter
capacitors. If the bleeders are 200K ohms and the filters are 1000 uF,
then they should be almost completely discharged in 200K * 1000 uF * 5
= 1000 seconds. "



http://forums.silentpcreview.com/viewtopic.php?t=6123
larrymoencurly
"
A 6800 uF capacitor (about ten times the size of those in ATX PSUs)that
I charged to 18V several months ago is currently at 13.4V, so I
wouldn't rely upon leaving the PSU unplugged for several weeks to drain
off the voltage.

Some of my PSUs make a noise just before the LED on the mobo goes dim,
and it's never taken more than twenty seconds. If for some reason this
doesn't work, then PSUs usually have or are supposed to have an approx.
200K ohm resistor across each big high voltage capacitors, and if this
capacitor is 1,000 uF, then the resistor should discharge it in 200K
ohms X 1,000uF X 5 = 1,000 seconds, or 16.7 minutes. Unless a resistor
or something else around one of those capacitors looks burnt or
ruptured, then the resistors have probably done their job. But you have
to know what those resistors look like.
"

thanks

 

[kony]

I'll check how long my ATX(so, with 5VSB) takes to discharge. with a
multimeter on 5VSB.

According to this guy quoted below, 1000 seconds (16.6 minutes). Though
it seems he didn't take into account the 5VSB+control circuit that you
mention.

First, understand the effect of a bleeder resistor- it is a
fixed resistance such that the lower the caps are bled, the
lower their voltage is, the slower the remaining voltage is
bled off.

We don't have to care if the caps are drained down to 0.0V,
not even 10V, only that they are drained down to a safe
level. There can be some disagreement about how high a
voltage is safe, but we can be quite conservative and just
pick a very low voltage, perhaps 25V (which right now, I can
touch between two fingers without even the slightest
sensation from it.

He also suggested that some may not have the restistors. And perhaps
some may have different rated resistors

These are certianly possible, but rather than drift around
in various details, we can instead focus on the primary
issue, whether ANY ATX PSU retains a dangerous charge after
having been unplugged for a few minutes. So far, nobody has
ever found one AFAIK.

Most are drained to a safe level in under 30 seconds. Some
in half that or less, particularly if it was still hooked up
to the system when unplugged instead of isolated with no
5VSB load.

http://forums.silentpcreview.com/viewtopic.php?t=3361&view=previous
larrymoencurly
"There are bleeder resistors across the big high voltage filter
capacitors. If the bleeders are 200K ohms and the filters are 1000 uF,
then they should be almost completely discharged in 200K * 1000 uF * 5
= 1000 seconds. "

"Completely discharged" will take an infinitely long time if
only considering these isolated variables because of the
issue presented above, that the further the voltage drops,
the slower the discharge rate. A half-life figure might be
more useful, but we still don't need to be concerned because
we can in fact measure these things, and I have several
times because I repair ATX PSU. I've even posted specific
measurements of one I'd disassembled and hooked up expressly
for the purpose of timing the discharge (not in this thread,
was months or maybe even a couple years ago (time flies!)).

http://forums.silentpcreview.com/viewtopic.php?t=6123
larrymoencurly
"
A 6800 uF capacitor (about ten times the size of those in ATX PSUs)that
I charged to 18V several months ago is currently at 13.4V, so I
wouldn't rely upon leaving the PSU unplugged for several weeks to drain
off the voltage.

It is true that a cap can hold a charge for a very long
time, but we are not considering a disconnected cap, we are
considering a whole ATX PSU. If one wants to argue that
perhaps these load resistors were to blow out and that would
be a problem, then it would only be reasonable to wonder
about any and all other potential problem in life,
ultimately cocluding that use of electrically powered
products in general are not safe, we shouldn't use ANY of
them.

Show one ATX PSU that retains a dangerous voltage level
after being unplugged for 5 minutes. There has to be a
first one if it's even remotely realistic to consider.

 

[Rod Speed]

(e-mail address removed) wrote

Rod Speed wrote

Running the PSU out of the case is a more sensible test,

Irrelevant when he has ALREADY tried another power supply.

and it'll be done anyway.

You have absolutely no idea what he will do.

I would use the results of that one,

More fool you when he has ALREADY tried another power supply.

since we're unavoidably doing it anyway.

Wrong again.

In practice, there are times when one makes assumptions that are
quite reasonable to make, in narrowing down a problem, and then
you hit a wall, and on reevaluating it from scratch with a fresh mind,
you realise one of the assumptions is wrong. It is very rare that a
fair assumption proves wrong, but it happens sometimes.

Waffle when he has already tried a different power supply.

THAT PROVES THAT IT CANT BE THE POWER SUPPLY.

In his case, there's a slight chance that both PSUs have the
same problem of rattling inside from the wire hitting the fan.

Nope, doesnt explain the lifting effect.

And when he lifts the case it moves that cable a bit.

Mindlessly silly with two different power supplys.
They wont both have that very unusual fault.

And there may be unforeseen issues too
that cause one to question assumptions.

Not in this particular case where he has already tried
two different power supplys, and sees that lifting effect.

So i'm not going to jump into assumptions.

You're a fool if you cant manage to grasp that there
is no assumption involved once he has tried two
different power supplys and he has that lifting effect.

It's good to double check, and choose your tests carefully.

Nope, not in this particular situation. Its only worth doing that if
he has eliminated any possibility of the noise being due to the
case and didnt see the lifting effect. THEN it would be worth
eliminating the very unlikely possibility that two completely
different power supplys have the same quite rare problem.

And when looking at possible problems,solutions and tests,
it's a good idea to double check, especially if a double check
takes 0 seconds(it being patr of another necessary check).

Mindless waffle in this particular situation.

I'll give you one of the rare examples where I've made an
assumption - or rather assigned a wrong probability (since
I am willing to revaluate from scratch with a fresh mind
ignoring assumptions. Since one is only human. ).

Irrelevant to what makes sense in this particular situation.

What you are doing, is making assumptions absolute.

Wrong, there is no assumption what so ever involved
in the particular diagnosis being discussed.

I might find myself saying "I find it hard to believe that this
is the problem..." or "this is most likely, this is unlikely".
And I do rule things out.. But not permanently. And in
deciding tests and possible solutions, I look at how much
time they'll take. If it's a great test and it takes 0 seconds,
i'm all for it. And i'm not against doing it twice to be sure!

More mindless waffle with the particular problem being discussed.

the method is snippnig and interleave.

Nope, I didnt snip a thing. I usually dont snip.

It applied here.
Nope.

And out of interest, were these 'bleed resistors'
also on all old AT power supplies and All ATX PSUs?

Irrelevant with the ATX PSU being discussed.