How to test a power supply ?

Hello,

Some have suggested to buy a voltmeter and then test the power supply.

Since computers have special plugs and such, how would one go about
testing the power supply ?

Are there special plugs necessary ?

(Not that I would ever try it, way to dangerous !)

Do you have a link to a website with some pictures ?

Bye,
Skybuck.

Skybuck wrote:
> Hello,
>
> Some have suggested to buy a voltmeter and then test the power supply.
>
> Since computers have special plugs and such, how would one go about
> testing the power supply ?
>
> Are there special plugs necessary ?
>
> (Not that I would ever try it, way to dangerous !)
>
> Do you have a link to a website with some pictures ?
>
> Bye,
> Skybuck.
>
>
How about buying a power supply tester, they sell them pretty cheap.

--
"Out here on the perimeter there are no stars"

Steve --Inglo--

'Skybuck' wrote:
| Some have suggested to buy a voltmeter and then test the power supply.
|
| Since computers have special plugs and such, how would one go about
| testing the power supply ?
|
| Are there special plugs necessary ?
|
| (Not that I would ever try it, way to dangerous !)
|
| Do you have a link to a website with some pictures ?
_____

All mains voltage is contained within the metal ATX power supply box. Just
follow basic safety proceedure used when working on ANY device connected to
mains voltage (i.e. don't stick screwdrivers into the supply when it is
plugged in.)

Keep in mind that mains voltage is ALWAYS present in the ATX power supply
EVEN when the system front panel switch is turned off AND the power switch
(if any) on the back of the power supply is turned off as long is the power
cord is plugged into the mains.

The System front panel switch just handles logic level voltages. However,
you must supply a POWER ON logic level TO the power supply to get it to turn
on.

Diagrams and specifications for the ATX power supply are at
http://www.formfactors.org/developer...public_br2.pdf .
Included are pinouts for the various power plugs.

A digital voltmeter should be used for measuring voltages.

The voltages under no load will not be representative of the voltages under
load. Voltage measurements when the system is operating are much more
useful. Thus the reason for system monitoring chips.

A good computer repair shop is recommended.

Phil Weldon

"Skybuck" <> wrote in message
news: oups.com...
| Hello,
|
| Some have suggested to buy a voltmeter and then test the power supply.
|
| Since computers have special plugs and such, how would one go about
| testing the power supply ?
|
| Are there special plugs necessary ?
|
| (Not that I would ever try it, way to dangerous !)
|
| Do you have a link to a website with some pictures ?
|
| Bye,
| Skybuck.
|

Skybuck <> wrote in news:1181362277.933852.227520
@k79g2000hse.googlegroups.com:

> Hello,
>
> Some have suggested to buy a voltmeter and then test the power supply.
>
> Since computers have special plugs and such, how would one go about
> testing the power supply ?
>
> Are there special plugs necessary ?
>
> (Not that I would ever try it, way to dangerous !)
>
> Do you have a link to a website with some pictures ?

http://www.compusa.com/products/prod...&product_code=
332184&Pn=ATX_12V_Version_2_0_Power_Supply_Tester

They have them right in the store if you have a CompUSA local to you.

Skybuck wrote:
> Hello,
>
> Some have suggested to buy a voltmeter and then test the power supply.
>
> Since computers have special plugs and such, how would one go about
> testing the power supply ?
>
> Are there special plugs necessary ?
>
> (Not that I would ever try it, way to dangerous !)
>
> Do you have a link to a website with some pictures ?
>
> Bye,
> Skybuck.
>

Phil provided a nice link to the pinout on a 24 pin supply (PDF page 37)

http://www.formfactors.org/developer...public_br2.pdf

Some people have recommended having a little bit of load on the power
supply. (Whether the power supply can be damaged by operating without a
load, is open to question. Maybe an older design can be damaged.)

To load my power supplies, I have a load box I built. It uses resistors
on each output rail, to place a light load on the supply for testing.
Construction cost might be $50 to $100. (The little power supply tester
dongle you can buy, only loads one rail, so I guess that is enough.)

http://groups.google.ca/group/alt.co...b?dmode=source

Without a minimum load, some power supplies are not guaranteed to be
within regulation. The output voltage might not be within 5%, if no
load is present. In some cases, if you look at the label on the side
of the supply, it will list both a maximum current (most will have that
info) while some will also list the minimum current.

So if you ignore that little detail, turning on the supply is easy.

1) Disconnect the power supply from the computer.
2) Plug in the power supply. Flip the power supply switch to ON.
3) Use a paper clip to connect PS_ON# to COM. PS_ON# is a green wire,
and COM is a black wire. There is a COM on either side of the PS_ON#
signal. You can use any COM signal, with the PS_ON# signal.
4) As long as the paper clip is in place, the power supply fan should
spin, and all voltages should be present.
5) When the paper clip is removed, only +5VSB will still be present and
providing power.
6) When the main switch on the back, is put in the OFF position, no voltages
should be present on the main connector.

HTH,
Paul

On Fri, 08 Jun 2007 21:11:17 -0700, in sci.electronics.design Skybuck
<> wrote:

>Hello,
>
>Some have suggested to buy a voltmeter and then test the power supply.
>
Make sure you get a voltmeter with a USB connector, in case you have
to reinstall the OS on the voltmeter


martin

'martin' wrote:
| Make sure you get a voltmeter with a USB connector, in case you have
| to reinstall the OS on the voltmeter
_____

Actually, you CAN get Digital Multimeters with serial and USB ports - for
logging, and, I suppose, for flash updates for the more sophisticated DMMs.

Phil Weldon

"martin griffith" <mart_in_medina@ya___.es> wrote in message
news:...
| On Fri, 08 Jun 2007 21:11:17 -0700, in sci.electronics.design Skybuck
| <> wrote:
|
| >Hello,
| >
| >Some have suggested to buy a voltmeter and then test the power supply.
| >
| Make sure you get a voltmeter with a USB connector, in case you have
| to reinstall the OS on the voltmeter
|
|
| martin

On Sat, 09 Jun 2007 18:12:43 GMT, in sci.electronics.design "Phil
Weldon" <> wrote:

>'martin' wrote:
>| Make sure you get a voltmeter with a USB connector, in case you have
>| to reinstall the OS on the voltmeter
>_____
>
>Actually, you CAN get Digital Multimeters with serial and USB ports - for
>logging, and, I suppose, for flash updates for the more sophisticated DMMs.
>
>Phil Weldon
>
>"martin griffith" <mart_in_medina@ya___.es> wrote in message
>news:.. .
>| On Fri, 08 Jun 2007 21:11:17 -0700, in sci.electronics.design Skybuck
>| <> wrote:
>|
>| >Hello,
>| >
>| >Some have suggested to buy a voltmeter and then test the power supply.
>| >
>| Make sure you get a voltmeter with a USB connector, in case you have
>| to reinstall the OS on the voltmeter
>|
>|
>| martin
>
Yes I know, but considering all the problems the OP is having with
bios and stuff, I thought I would just add to his confusion


martin

"Inglo" <ioo@??.¿¿¿> wrote in message
news:UYqai.32537$. net...
> Skybuck wrote:
>> Hello,
>>
>> Some have suggested to buy a voltmeter and then test the power supply.
>>
>> Since computers have special plugs and such, how would one go about
>> testing the power supply ?
>>
>> Are there special plugs necessary ?
>>
>> (Not that I would ever try it, way to dangerous !)
>>
>> Do you have a link to a website with some pictures ?
>>
>> Bye,
>> Skybuck.
>>
>>
> How about buying a power supply tester, they sell them pretty cheap.
>


They are basically useless. The only way to fully test a PSU is under load.
If has to be plugged in and the computer needs to be running. A voltmeter is
the only way to go. Just because a PSU works when its not under load ie
using a PSU tester does not mean it wont fail under load, once its gotten
good and warm.

Dan

"Angry_American" <> schreef in bericht
news:466b39ce$0$6577$ g.com...
> "Inglo" <ioo@??.¿¿¿> wrote in message
> news:UYqai.32537$. net...
>> Skybuck wrote:
>>> Hello,
>>>
>>> Some have suggested to buy a voltmeter and then test the power supply.
>>>
>>> Since computers have special plugs and such, how would one go about
>>> testing the power supply ?
>>>
>>> Are there special plugs necessary ?
>>>
>>> (Not that I would ever try it, way to dangerous !)
>>>
>>> Do you have a link to a website with some pictures ?
>>>
>>> Bye,
>>> Skybuck.
>>>
>>>
>> How about buying a power supply tester, they sell them pretty cheap.
>>
>
>
> They are basically useless. The only way to fully test a PSU is under
> load. If has to be plugged in and the computer needs to be running. A
> voltmeter is the only way to go. Just because a PSU works when its not
> under load ie using a PSU tester does not mean it wont fail under load,
> once its gotten good and warm.
>
> Dan

You better change your name in stupid american like the rest.
Stop crossposting !
fup set