Actually, I'm sure the power supply he bought from the store is
perfectly fine. Don't forget about "power good"! If the power supply
doesn't see this, it will not stay on. That is how all ATX power
supplies are designed, and it is indeed built-in component protection.
If anything is shorting out (as could very well be the case here, since
his first power supply fried something), it will shut down a working
power supply.
Actually, I'm sure the power supply he bought from the
store is perfectly fine. Don't forget about "power good"!
If the power supply doesn't see this, it will not stay on.
That is how all ATX power supplies are designed,
Nope.
and it is indeed built-in component protection. If anything is shorting
out (as could very well be the case here, since his first power supply
fried something), it will shut down a working power supply.
Rod Speed said:You've got that backwards, its PROVIDED by the
power supply, not observed by the power supply.
Good link on the Power Good Signal
http://www.pcguide.com/ref/power/sup/funcPowerGood-c.html
and how "Some extremely el-cheapo power supplies may "fake" the Power
Good signal by just tying it to another +5 V line."
It works both ways.
Yes, it is provided by the power supply, and yes, it is there to prevent
the motherboard from starting up before the power supply stabilizes.
However, on some power supplies, if there is a power
surge or any other issue (which can be caused by a
fried component on the motherboard), "Power Good"
will also shut down the power supply if it malfunctions.
David Matthew Wood said:(e-mail address removed) wrote
Yes, and while it doesn't directly have anything to do with Power
Good, such power supplies don't provide any protection either.
If you try to fire up a GOOD supply and it doesn't observe the correct
loads (either from not being properly connected or from something that
is shorting), it will shut down in order to prevent damage
since it is bad for a power supply to run without a load.
Same goes with amps.
If you power up an amp and crank the volume without speakers attached,
it will either a, go into thermal shut down, or b, self-destruct.
Rod Speed said:You dont know that on that ANY claim.
Yes. But that is true even with cheap power supplys too.
Where they mostly fail is shutting down properly when the power supply fails.
Oh bullshit.
Nope, completely different.
Utterly mangled all over again.
Rod Speed said:Nope, its an output FROM the power supply, not an input TO the power supply.
Nothing like what you originally said.
Nope, again, its an output FROM the power supply and the power
supply is supposed to drop the power good signal if something has
gone bad power wise, mainly so the motherboard can restart after
a glitch that has seen the power supply shut down and then start again.
The power supply doesnt even notice a fried component
on the motherboard unless that produces a higher than
allowed current on one of the rails it produces.
What, that cheap POS power supplies don't
shut down right away if something is shorting?
Well lets see. I have some sitting around that will not power
up at all because something in the machine shorted them out.
I have others sitting around that still power up and
work just fine after being shorted out, because they
shut down right away before damage was done.
Shutting down before damage is done you mean.
Yep.
I've witnessed both.
A, something will short out and PS will smoke.
or
B, something will short out and PS will turn off. In which
case, after dealing with whatever caused the short, the
power supply will come to life and work just fine.
Oh really? Why don't you try it then.
Force a cheap power supply on and let it run
for a while without a load. See what happens.
Again...oh really?
Take a high current amplifier, give it an audio feed,
disconnect anything that will create a load on the
outputs, crank the levels, and see what happens.
It doesn't matter.
Some supplies monitor that load.
I have quite a few that will shut down if load on PG does not exist.
No, I'm half agreeing with you about what power good is there for.
And some supplies shut down completely.
I have a few sitting right here that will do that.
And now we go back to the original post where the OP said that his
new power supply would not stay on - not because it was bad, but
because there was an issue with something it was powering up.
As it turned out, once he cleared up that issue, all was well.
Well lets see. I have some sitting around that will not power
up at all because something in the machine shorted them out.
Plenty of cheap power supplys do that fine.
Yes, so you claim that they dont have ANY protection is just plain wrong.
Done that plenty of times thanks.
Fraid so.
Nothing special with a properly designed amp.
Because it isnt hard to accidentially disconnect a speaker.
And do you know this exactly?
I've seen it happen firsthand.
Maybe,
but not as likely as it would be if it weren't a power
supply where corners were cut in making it.
I was replying to an article that mentioned how some
skimp on PG and just supply a normal 5v lead instead.
If a power supply is built like that, then it's very likely corners
were cut in other areas too, including the protection circuitry.
Consider yourself lucky then.
All amps come with manuals that say to NEVER operate
them without a proper load. There are reasons for this.
Again, consider yourself lucky.
Either you weren't running much power through this thing,
or you caught it in a short time - or you weren't running the
amp much beyond 20% of its capacity with a constant signal
running through it.
Rod Speed said:I know that you cant be sure why they have failed.
Or assumed that they got killed by the machine shorting them out
when they may have died and killed what is powered from them.
That last isnt that uncommon with cheap power supplys.
No maybe about it.
Wrong, there arent many so badly designed that they
dont shut down when one of the rails is shorted.
Plenty more fail and kill what is powered by the power supply.
Yes, but that isnt necessarily the end of the world
if the design ensures that that comes up last.
Not necessarily if the supply ensures that that 5V rail comes up last.
And you claimed that they dont have ANY protection. Even
the cheapest power supply have SOME protection even if
they dont necessarily adequately protect against the power
supply over voltaging some of the rails as it dies.
Essentially because that sort of independant protection against
any output rail going out of spec costs more to provide.
yes..
Nope, I know that wont kill a power supply.
Doesnt mean they will be killed by the accidental disconnection of a speaker.
No thanks, I know that wont kill a properly designed amp.
Easy to claim. I manage to fry the speakers
by over driving them and the amp was fine.
Um.... no.
Many years ago, I overestimated the space between the
bottom of a hard drive and the metal frame of the case.
Turned machine on, drive control board shorted and
smoked. Because of this short, power supply also
smoked. How is that an assumption exactly?
And again later, I unknowingly had a bad power
connector which turned out to be shorted.
Fired up the supply, it came on for not even half
a second, and turned itself off again. Short was
cleared, power was fired up again, and all was well.
Plenty maybe about it, it all depends on design.
I had one smoke due to this.
Yes, and the better designed supplies shut down
before this happens - just as the better designs shut
off in time to save themselves if they are shorted.
And not all of them do.
-sigh-
protection as in protecting the power
supply itself, which is what I meant.
In other words, its ability to shut itself down BEFORE damage
is done to the supply, which was the original case of this thread.
The OP's power supply died. He went to the store and bought
another one, and put it in his machine. He went to fire it up, it
shut down right afterwards. The OP then corrected a wiring problem,
fired it up again without changing any components, and all was good.
If I had wanted to go any further than that, I could have just said that
the fuse in your mains fuse box IS the protection - not against equipment,
but against fire... but perhaps I should have stated this anyway.
Then why do the manufacturers of these
very supplies advise against this?
Accidental disconnection of a speaker, which is usually caught shortly
afterwards since you're now not hearing sound out of this speaker.
If this condition were allowed to continue and you ran the
amp at constant high power, it will eventually kill the amp
- if it doesn't trip the protection circuits first!
Well since you seem to know more than the people who made
these amps, all of whom say NEVER run an amp without a load...
And while these speakers are being over driven, you
are still driving them and thus the amp is seeing a load!
How long after completely melting the speaker
coils, have you run this amp exactly?
How long have you let it run under constant high power without
a load? Do you actually test this by turning the volume up higher
and higher AFTER you manage to blow the speakers?
Rod Speed <rod.speed.aaa gmail.com> wrote
Um.... no.
Many years ago, I overestimated the space between the
bottom of a hard drive and the metal frame of the case.
Turned machine on, drive control board shorted and
smoked. Because of this short, power supply also
smoked. How is that an assumption exactly?
And again later, I unknowingly had a bad power
connector which turned out to be shorted.
Fired up the supply, it came on for not even half
a second, and turned itself off again. Short was
cleared, power was fired up again, and all was well.
Plenty maybe about it, it all depends on design.
I had one smoke due to this.
Yes, and the better designed supplies shut down
before this happens - just as the better designs shut
off in time to save themselves if they are shorted.
And not all of them do.
-sigh-
protection as in protecting the power
supply itself, which is what I meant.
In other words, its ability to shut itself down BEFORE damage
is done to the supply, which was the original case of this thread.
The OP's power supply died. He went to the store and bought
another one, and put it in his machine. He went to fire it up, it
shut down right afterwards. The OP then corrected a wiring problem,
fired it up again without changing any components, and all was good.
If I had wanted to go any further than that, I could have just said that
the fuse in your mains fuse box IS the protection - not against equipment,
but against fire... but perhaps I should have stated this anyway.
Then why do the manufacturers of these
very supplies advise against this?
Accidental disconnection of a speaker, which is usually caught shortly
afterwards since you're now not hearing sound out of this speaker.
If this condition were allowed to continue and you ran the
amp at constant high power, it will eventually kill the amp
- if it doesn't trip the protection circuits first!
Well since you seem to know more than the people who made
these amps, all of whom say NEVER run an amp without a load...
And while these speakers are being over driven, you
are still driving them and thus the amp is seeing a load!
How long after completely melting the speaker
coils, have you run this amp exactly?
How long have you let it run under constant high power without
a load? Do you actually test this by turning the volume up higher
and higher AFTER you manage to blow the speakers?
We'll see...
That is just one example, you butcher.
Nothing at all unusual about, thats the way its sposed to work.
Nope, most cheap supplys handle that fine.
YOU claimed that they didnt have ANY protection.
That is clearly just plain wrong when they handle a shorted output fine.
The technical term for that is 'pathetically inadequate sample'
Whatever.
No one ever claimed that no power supplys have ever failed
like that, what was being discussed was your stupid pig ignorant
claim that some cheap supplys dont have ANY protection.
Irrelevant to your stupid pig ignorant claim that
some cheap supplys dont have ANY protection.
Still completely silly. If that was actually the case they wouldnt
last long as there are always some spikes on the mains.
You made a general claim about el cheapo power supplys.
Irrelevant to your stupid pig ignorant claim that
some cheap supplys dont have ANY protection.
They dont.
Irrelevant to that stupid pig ignorant claim of yours.
Not a ****ing clue, as always.
Funny that. They're there for a reason.
Took a while to notice that one side had died.
Didnt need to, your claim is pig ignorant drivel. The reason the
speakers got fried was because the volume was WAY up.
An example, nonetheless. I can give you a few more if need be.
And yet it isn't as reliable on poor cheap
designs - some of which will just blow.
The ones that handled shorted outputs were
not the cheapest power supplies either...
And some don't, unless you count the protection that only
serves to prevent fires and does nothing to save the equipment.
Protection against equipment damage is what I meant.
I'm sorry I didn't state that correctly.
No, because the spike on the mains is within tolerance.
Saying it's not, is like saying a fuse that is properly
rated will blow right away on an initial normal start up
surge caused by heavy equipment - which it should not.
Ok, I shall reword it next time.
More childish insults ignored.
Some do.
It depends on the design.
That is why in general (and for the purpose of 24hoursupport.helpdesk),
I say don't attempt it for a long period of time without knowing the design.
How is it irrelevant when the change of damage occurring
is minimized if this situation is caught early enough?
Even more childish insults ignored.
Yes, to prevent damage to the output transformers from
attempting to run it without a load - or in the case of a short!
Lucky you didn't blow the output transformer.
And once the speakers got fried, you continued to run it in this
condition for several minutes afterwards, running the amp at capacity?
Yep.
Most people don't..
An example, nonetheless. I can give you a few more if need be.
**** all in fact.
And that that proves nothing about your stupid claim that
some cheap power supplys dont have ANY protection.
Pity that that proves nothing about your stupid claim that
some cheap power supplys dont have ANY protection.
Pity that claim is STILL just plain wrong.
Mindlessly silly.
Nothing like in fact. To survive normal mains spikes,
THE SUPPLY MUST HAVE SOME PROTECTION.
Still just plain wrong in the latest version.
No they dont.
No it doesnt.
You never said anything about how long in the original.
There are no 'output transformers'
And any decent designed amp has that protection to prevent any
damage when the inevitable happens, the speakers get disconnected.
Yep.