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Dead AT power supply

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Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 4:07:55 PM

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

I have a slot1 PC that won't power on. My roommate reports that something
smelled burnt when it suddenly powered off. When I checked it out the system
would only power on for a short spurt then go dead after a second, so I'm
suspecting the PSU is shot. Unfortunately, the power connectors on the PSU
consist of 2 6pin connectors and a 3pin standby power connector. I'm assuming
that the unit is an AT model, but I don't know where to find one that has a
standby power connector. Any suggestions other than "buy a new PC" would be
appreciated.

More about : dead power supply

Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 4:07:56 PM

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

Ed Coolidge wrote:
> I have a slot1 PC that won't power on. My roommate reports that
> something smelled burnt when it suddenly powered off. When I checked it
> out the system would only power on for a short spurt then go dead after
> a second, so I'm suspecting the PSU is shot. Unfortunately, the power
> connectors on the PSU consist of 2 6pin connectors and a 3pin standby
> power connector. I'm assuming that the unit is an AT model, but I don't
> know where to find one that has a standby power connector. Any
> suggestions other than "buy a new PC" would be appreciated.

It's an AT PSU, from a particular manufacturer, but you gave no clue as to
who made the computer.

It could be the PSU or anything in the computer that's failed (CPU or
motherboard being common failure points in addition to the PSU) and
overloading it.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 4:07:56 PM

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

In article <vE3de.2102$pe3.210@newsread3.news.atl.earthlink.net>,
Ed Coolidge <semi_DELETE_THIS_charm@earthlink.net> wrote:
>I have a slot1 PC that won't power on. My roommate reports that something
>smelled burnt when it suddenly powered off. When I checked it out the system
>would only power on for a short spurt then go dead after a second, so I'm
>suspecting the PSU is shot. Unfortunately, the power connectors on the PSU
>consist of 2 6pin connectors and a 3pin standby power connector. I'm assuming
>that the unit is an AT model, but I don't know where to find one that has a
>standby power connector. Any suggestions other than "buy a new PC" would be
>appreciated.


Dumpster, flea market, yard sale.

--
a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
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Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 4:39:15 PM

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

The PC is an Acer Power 8000, or at least that's the best I can determine as
Acer has no record of the serial number. The only change that's been made was a
CPU upgrade that's been working fine for a month. I've unplugged all of the
drives and removed all of the cards except memory and video so I know it's not
overloaded. I tested it with the old CPU, but the results are the same. The PC
only has one 128MB RAM card and I don't have any spare RAM to test with it. I
tested the RAM a few weeks ago and it checked out OK. The power LED on the case
does light orange if that helps. I suspected that it might be the mainboard
too, but without swapping out the PSU I have no way to tell.

David Maynard wrote:

> It's an AT PSU, from a particular manufacturer, but you gave no clue as
> to who made the computer.
>
> It could be the PSU or anything in the computer that's failed (CPU or
> motherboard being common failure points in addition to the PSU) and
> overloading it.
>
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 4:39:16 PM

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

Ed Coolidge wrote:

> The PC is an Acer Power 8000, or at least that's the best I can
> determine as Acer has no record of the serial number. The only change
> that's been made was a CPU upgrade that's been working fine for a
> month. I've unplugged all of the drives and removed all of the cards
> except memory and video so I know it's not overloaded. I tested it with
> the old CPU, but the results are the same. The PC only has one 128MB
> RAM card and I don't have any spare RAM to test with it. I tested the
> RAM a few weeks ago and it checked out OK. The power LED on the case
> does light orange if that helps. I suspected that it might be the
> mainboard too, but without swapping out the PSU I have no way to tell.

Well, I found the user manual for it and it shows the connectors on the
motherboard but, interestingly enough, it doesn't say to plug the 3 pinner
in when installing a PSU.

You may have to get one from an Acer distributor.

>
> David Maynard wrote:
>
> > It's an AT PSU, from a particular manufacturer, but you gave no clue as
>
>> to who made the computer.
>>
>> It could be the PSU or anything in the computer that's failed (CPU or
>> motherboard being common failure points in addition to the PSU) and
>> overloading it.
>>
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 4:43:51 PM

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

Al Dykes wrote:

> Dumpster, flea market, yard sale.

Yes, but I don't believe that standby power connectors are common for AT units.
I would swap the PSU and the mainboard, but I don't know where to find a slot1
board on short notice as my roommate wants his PC back.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 5:21:13 PM

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

Just a thought, is there any way to start the PSU without the mainboard? All it
should need is the right signal on the standby connector, but I'm not sure what
that would be.


David Maynard wrote:


> It's an AT PSU, from a particular manufacturer, but you gave no clue as
> to who made the computer.
>
> It could be the PSU or anything in the computer that's failed (CPU or
> motherboard being common failure points in addition to the PSU) and
> overloading it.
>
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 5:21:14 PM

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

Ed Coolidge wrote:

> Just a thought, is there any way to start the PSU without the
> mainboard? All it should need is the right signal on the standby
> connector, but I'm not sure what that would be.

There probably is but I can't find a pin out for the 3 pin connector, off hand.

You could try disconnecting the two 6 pin jobs and try powering it up with
the 3 pin still in the motherboard and hope the on/off switch works.


> David Maynard wrote:
>
>
>> It's an AT PSU, from a particular manufacturer, but you gave no clue
>> as to who made the computer.
>>
>> It could be the PSU or anything in the computer that's failed (CPU or
>> motherboard being common failure points in addition to the PSU) and
>> overloading it.
>>
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 6:39:49 PM

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

I can't find any info on the pin out either. Just for kicks I checked it
without the 2 6pin connectors and the PSU fan starts up as soon as I connected
the power cord. The switch didn't make any difference. So if it's the
mainboard that's failed I would have to replace the PSU anyway.

David Maynard wrote:


> There probably is but I can't find a pin out for the 3 pin connector,
> off hand.
>
> You could try disconnecting the two 6 pin jobs and try powering it up
> with the 3 pin still in the motherboard and hope the on/off switch works.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 7:01:44 PM

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

Again, just for kicks, I figured that if the PSU is indeed on when connected
with only the standby connector it should be able to power a drive, so I tried
connecting a CD drive. At first it just wouldn't budge, but then I thought that
having ground to the host controller might be the problem, so I tried it again
without the data cable. the drive spun up just fine and the tray worked too. So
what do you think, dead mainboard?

Ed Coolidge wrote:

> I can't find any info on the pin out either. Just for kicks I checked
> it without the 2 6pin connectors and the PSU fan starts up as soon as I
> connected the power cord. The switch didn't make any difference. So if
> it's the mainboard that's failed I would have to replace the PSU anyway.
>
> David Maynard wrote:
>
>
>> There probably is but I can't find a pin out for the 3 pin connector,
>> off hand.
>>
>> You could try disconnecting the two 6 pin jobs and try powering it up
>> with the 3 pin still in the motherboard and hope the on/off switch works.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 7:01:45 PM

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

Ed Coolidge wrote:

> Again, just for kicks, I figured that if the PSU is indeed on when
> connected with only the standby connector it should be able to power a
> drive, so I tried connecting a CD drive. At first it just wouldn't
> budge, but then I thought that having ground to the host controller
> might be the problem, so I tried it again without the data cable. the
> drive spun up just fine and the tray worked too. So what do you think,
> dead mainboard?

Sounds like either that or the processor.

If it's the main board I'd bet it's either the Vcore regulator or caps.
Check the large caps around the CPU to see if any are bulged or leaking.

Also, try power the mainboard with no CPU, memory, or anything. It won't
run, of course, but the point is to see if the PSU will stay up.

>
> Ed Coolidge wrote:
>
>> I can't find any info on the pin out either. Just for kicks I checked
>> it without the 2 6pin connectors and the PSU fan starts up as soon as
>> I connected the power cord. The switch didn't make any difference.
>> So if it's the mainboard that's failed I would have to replace the PSU
>> anyway.
>>
>> David Maynard wrote:
>>
>>
>>> There probably is but I can't find a pin out for the 3 pin connector,
>>> off hand.
>>>
>>> You could try disconnecting the two 6 pin jobs and try powering it up
>>> with the 3 pin still in the motherboard and hope the on/off switch
>>> works.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 1, 2005 9:32:47 PM

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

Well, I've already tried using the old processor, which I know is still good.
I've pulled everything and still no go. There's a row of 4 caps behind the slot
that are bulging on top. I guess it's time to pull the cover over this patient.

BTW, a main board won't start without a CPU. Once I mounted an AMD Tbird
without locking the socket first (and yes, the heatsink was small enough to
clear the level).

David Maynard wrote:

> Sounds like either that or the processor.
>
> If it's the main board I'd bet it's either the Vcore regulator or caps.
> Check the large caps around the CPU to see if any are bulged or leaking.
>
> Also, try power the mainboard with no CPU, memory, or anything. It won't
> run, of course, but the point is to see if the PSU will stay up.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 2, 2005 5:42:48 AM

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

Ed Coolidge wrote:
> Well, I've already tried using the old processor, which I know is still
> good. I've pulled everything and still no go. There's a row of 4 caps
> behind the slot that are bulging on top. I guess it's time to pull the
> cover over this patient.

The bulging caps are certainly bad. Whether they took the regulator too, or
it took them, or they simply went on their own you can't tell just by looking.

I'd replace them but then not everyone is comfortable soldering.

Actually, the first thing I would do is simply pry them off; which isn't as
hard as it might seem as the wires will pull out of the cap case. And then
I'd try powering the board up with no processor, memory, or anything else
in it. If it doesn't crowbar the PSU then there's a decent chance the Vcore
reg is ok and replacing the caps alone might fix it. If it still crowbars
the PSU then the Vcore FET is likely gone and I'd replace that too.


> BTW, a main board won't start without a CPU.

That's why I said "It won't run, of course" :) 

> Once I mounted an AMD
> Tbird without locking the socket first (and yes, the heatsink was small
> enough to clear the level).
>
> David Maynard wrote:
>
>> Sounds like either that or the processor.
>>
>> If it's the main board I'd bet it's either the Vcore regulator or
>> caps. Check the large caps around the CPU to see if any are bulged or
>> leaking.
>>
>> Also, try power the mainboard with no CPU, memory, or anything. It
>> won't run, of course, but the point is to see if the PSU will stay up.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 2, 2005 7:38:57 AM

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

Ed Coolidge wrote:
> Well, I've already tried using the old processor, which I know is still
> good. I've pulled everything and still no go. There's a row of 4 caps
> behind the slot that are bulging on top.

You could always have a go at replacing them. If you're going to junk it
anyway, where's the harm?

> I guess it's time to pull the
> cover over this patient.
>
> BTW, a main board won't start without a CPU. Once I mounted an AMD
> Tbird without locking the socket first (and yes, the heatsink was small
> enough to clear the level).
>
> David Maynard wrote:
>
>> Sounds like either that or the processor.
>>
>> If it's the main board I'd bet it's either the Vcore regulator or
>> caps. Check the large caps around the CPU to see if any are bulged or
>> leaking.
>>
>> Also, try power the mainboard with no CPU, memory, or anything. It
>> won't run, of course, but the point is to see if the PSU will stay up.


--
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I'm going to die rather sooner than I'd like. I tried to protect my
neighbours from crime, and became the victim of it. Complications in
hospital following this resulted in a serious illness. I now need a bone
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Anonymous
a b B Homebuilt system
a b ) Power supply
May 2, 2005 7:38:58 AM

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

At this point I'm not sure if it's worth trouble. I'm not that good at
soldering anyway.

spodosaurus wrote:

> You could always have a go at replacing them. If you're going to junk it
> anyway, where's the harm?
Anonymous
a b B Homebuilt system
a b ) Power supply
May 2, 2005 5:14:58 PM

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

David Maynard wrote:

> The bulging caps are certainly bad. Whether they took the regulator too,
> or it took them, or they simply went on their own you can't tell just by
> looking.
>
> I'd replace them but then not everyone is comfortable soldering.

I think I'll just face the fact that it's dead and leave it at that. It's not
that I'm uncomfortable with soldering, but rather not very good at it. I'll
check the local shops for used parts.

> That's why I said "It won't run, of course" :) 

I'm mean nothing would start, not even the PSU. There's no point in testing
something when it's not going to do anything.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 3, 2005 4:06:14 AM

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

Ed Coolidge wrote:

>
>
> David Maynard wrote:
>
>> The bulging caps are certainly bad. Whether they took the regulator
>> too, or it took them, or they simply went on their own you can't tell
>> just by looking.
>>
>> I'd replace them but then not everyone is comfortable soldering.
>
>
> I think I'll just face the fact that it's dead and leave it at that.
> It's not that I'm uncomfortable with soldering, but rather not very good
> at it. I'll check the local shops for used parts.

Entirely your choice.


>> That's why I said "It won't run, of course" :) 
>
>
> I'm mean nothing would start, not even the PSU. There's no point in
> testing something when it's not going to do anything.

I don't know if there's something 'special' about your motherboard, besides
being broke at the moment, but every one I've got powers up without CPU,
memory, or anything else, installed and I regularly check for shorted
mobos, and Vcore/mem voltages, that way rather than risk CPU and memory on
the first debug power up.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 3, 2005 4:33:01 PM

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

David Maynard wrote:

> I don't know if there's something 'special' about your motherboard,
> besides being broke at the moment, but every one I've got powers up
> without CPU, memory, or anything else, installed and I regularly check
> for shorted mobos, and Vcore/mem voltages, that way rather than risk CPU
> and memory on the first debug power up.
>

The busted one is a slot1, which obviously doesn't have a socket.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 3, 2005 9:31:57 PM

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

Ed Coolidge wrote:
> David Maynard wrote:
>
>> I don't know if there's something 'special' about your motherboard,
>> besides being broke at the moment, but every one I've got powers up
>> without CPU, memory, or anything else, installed and I regularly check
>> for shorted mobos, and Vcore/mem voltages, that way rather than risk
>> CPU and memory on the first debug power up.
>>
>
> The busted one is a slot1, which obviously doesn't have a socket.

Doesn't matter. I do the same with slot-1 boards with the same results.

Actually, you can think of the slot as a kind of 'linear socket'. The
reason for the cartridge was to fit the cache chips on-board and later they
went on-die with the coppermines, so it again fit in a socket form factor,
but the bus interface, I.E. the lines to the socket/slot, are essentially
the same (sans some termination resistors and decoupling caps); which is
why slotkets work.

The thing is, the processor and memory are not involved in the PSU
power-on/off circuit.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 4, 2005 3:53:51 PM

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

I know what a slot interface is, why they were used and why they are were phased
out. However, you missed the obvious point that I wasn't even talking about the
mainboard that died. The one that died was a Slot 1 and the other that I was
referring to has a socket, Socket A to be exact. And no the PSU would not even
start without the CPU. BTW the Socket A mainboard works just fine has I'm using
it right now.

David Maynard wrote:

> Doesn't matter. I do the same with slot-1 boards with the same results.
>
> Actually, you can think of the slot as a kind of 'linear socket'. The
> reason for the cartridge was to fit the cache chips on-board and later
> they went on-die with the coppermines, so it again fit in a socket form
> factor, but the bus interface, I.E. the lines to the socket/slot, are
> essentially the same (sans some termination resistors and decoupling
> caps); which is why slotkets work.
>
> The thing is, the processor and memory are not involved in the PSU
> power-on/off circuit.
>
Anonymous
a b B Homebuilt system
a b ) Power supply
May 5, 2005 3:07:49 AM

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

Ed Coolidge wrote:

> I know what a slot interface is, why they were used and why they are
> were phased out. However, you missed the obvious point that I wasn't
> even talking about the mainboard that died.

I'm sure it was all obvious on that end but by the time it gets over here,
with what was in your head stripped off, it wasn't nearly as obvious.

> The one that died was a
> Slot 1 and the other that I was referring to has a socket, Socket A to
> be exact. And no the PSU would not even start without the CPU. BTW the
> Socket A mainboard works just fine has I'm using it right now.

Normally I'd be curious as to what might keep it from powering up, like
maybe a loose processor rattling around in an unlatched socket having some
pins making contact while others weren't, or any number of things, but
since you're apparently wedded to the notion that a motherboard can't be
powered up without one we might as well leave it at that.



> David Maynard wrote:
>
> > Doesn't matter. I do the same with slot-1 boards with the same results.
>
>>
>> Actually, you can think of the slot as a kind of 'linear socket'. The
>> reason for the cartridge was to fit the cache chips on-board and later
>> they went on-die with the coppermines, so it again fit in a socket
>> form factor, but the bus interface, I.E. the lines to the socket/slot,
>> are essentially the same (sans some termination resistors and
>> decoupling caps); which is why slotkets work.
>>
>> The thing is, the processor and memory are not involved in the PSU
>> power-on/off circuit.
>>
Anonymous
a b B Homebuilt system
a b ) Power supply
May 5, 2005 4:19:03 PM

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

David Maynard wrote:
> I'm sure it was all obvious on that end but by the time it gets over
> here, with what was in your head stripped off, it wasn't nearly as obvious.

Sorry, I guess everyone confuses sockets with slots.

> Normally I'd be curious as to what might keep it from powering up, like
> maybe a loose processor rattling around in an unlatched socket having
> some pins making contact while others weren't, or any number of things,
> but since you're apparently wedded to the notion that a motherboard
> can't be powered up without one we might as well leave it at that.

Perhaps. If it wasn't such a pain to mount the heatsink on my AMD CPU I would
check to see if it was just a shorted pin. However I'm not just that curious at
the moment.
Anonymous
a b B Homebuilt system
a b ) Power supply
May 5, 2005 10:51:43 PM

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

Ed Coolidge wrote:
> David Maynard wrote:
>
>> I'm sure it was all obvious on that end but by the time it gets over
>> here, with what was in your head stripped off, it wasn't nearly as
>> obvious.
>
>
> Sorry, I guess everyone confuses sockets with slots.

No prob. In this case it was the comment "The busted one is a slot1, which
obviously doesn't have a socket" that caused the confusion on this end.
Sounded to me like you were trying to make some distinguishement between
how one with a socket vs one with a slot might behave, which was what
induced me to point out there shouldn't be a difference (at least from just
that).

>
>> Normally I'd be curious as to what might keep it from powering up,
>> like maybe a loose processor rattling around in an unlatched socket
>> having some pins making contact while others weren't, or any number of
>> things, but since you're apparently wedded to the notion that a
>> motherboard can't be powered up without one we might as well leave it
>> at that.
>
>
> Perhaps. If it wasn't such a pain to mount the heatsink on my AMD CPU I
> would check to see if it was just a shorted pin. However I'm not just
> that curious at the moment.

I wouldn't either at this stage.

The real point, regardless of what it might take to accomplish it, was that
testing the motherboard without risking the processor at the same time
was a useful debug tool.
July 31, 2008 3:37:53 AM

"standby connector" pinout:
red - 5V standyby power
black - ground
brown - power on signal

The PSU starts up when "power on signal" is connected to ground, and it shutoff when it is disconnected.

In short the Acer psu is a ATX psu with AT connector (minus the 3.3V supply pairs). ATX psu reconnected accordingly will works fine.
!