Powering up an ATX PS ?

[Darmok]

Hi,

I've got an ATX computer PS pulled from an old computer.

I know that 2 of the 20 pins on the ATX power plug have to be jumpered
in order for the thing to power up .. not sure which ones .. was it
13-14? ... Also, after those are jumped, what turns on the supply?
Normally, there's a push button on the computer which goes to a 2 pin
header on the MB, which I assume sends some sort of "power up" signal
to the ATX supply ... how do I fake that out?

Thanks,

Bill

 

[default]

Hi,

I've got an ATX computer PS pulled from an old computer.

I know that 2 of the 20 pins on the ATX power plug have to be jumpered
in order for the thing to power up .. not sure which ones .. was it
13-14? ... Also, after those are jumped, what turns on the supply?
Normally, there's a push button on the computer which goes to a 2 pin
header on the MB, which I assume sends some sort of "power up" signal
to the ATX supply ... how do I fake that out?

Thanks,

Bill

See http://www.pavouk.comp.cz/hw/en_atxps.html

For a schematic of an ATX supply. We owe Pavel Ruzicka for taking
the time to reverse engineer it. The info you're looking for is in
the theory of operation on the site.

The start up line 5V start bus is a separate tiny supply that is
running whenever the computer is plugged in (and turned on) It shares
the input rectifier and filters with the main supply but is otherwise
totally independent. A little three terminal regulator handles the
output.

 

[Jim Yanik]

See http://www.pavouk.comp.cz/hw/en_atxps.html

For a schematic of an ATX supply. We owe Pavel Ruzicka for taking
the time to reverse engineer it. The info you're looking for is in
the theory of operation on the site.

The start up line 5V start bus is a separate tiny supply that is
running whenever the computer is plugged in (and turned on) It shares
the input rectifier and filters with the main supply but is otherwise
totally independent. A little three terminal regulator handles the
output.

He probably needs a minimum load on the PS output,too,most likely the +5V
line.

 

[default]

He probably needs a minimum load on the PS output,too,most likely the +5V
line.

Possibly. The ATX diagram is representative of the type. In this
particular one both the +5 and +12 / -12 are referenced back to the
PWM via a voltage divider, which would suggest one or some
combination of supplies might need some minimum load to regulate
properly.

Hopefully he understands how dangerous the input circuits can be . . .
never mind the outputs.

The schematic does show some (minimal) load resistors on the outputs.

A good basic info on switching supplies:

http://repairfaq.ece.drexel.edu/sam/smpsfaq.htm

A better text on switching supplies with instructions on starting an
ATX and using a dummy load on the +5 supply:

http://www.wies-hs.eu.dodea.edu/Cou...puterServiceSupport/css/Forms/Doc/TrbPSGD.pdf

 

[[email protected]]

I think CompUSA sells a PS tester. This gets by all of those wiring and
switch problems. It is only about $20.00

 

[Sam Goldwasser]

I think CompUSA sells a PS tester. This gets by all of those wiring and
switch problems. It is only about $20.00

What more is there than jumpering the Power_Supply_On wire to ground with
a load on the output?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[DaveM]

What more is there than jumpering the Power_Supply_On wire to ground with
a load on the output?

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above
is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

That's pretty much all there is to those little cheapie testers... A
little box containing a minimal load, some LEDs that give a go//nogo
indication of all the voltages, a switch that lets you turn the PS on-off
from the box and an instruction sheet that was written by a Chinese
housewife and translated into English by a Russian schoolboy.
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in
the address)

Never take a laxative and a sleeping pill at the same time!!

 

[clifto]

That's pretty much all there is to those little cheapie testers... A
little box containing a minimal load, some LEDs that give a go//nogo
indication of all the voltages, a switch that lets you turn the PS on-off
from the box and an instruction sheet that was written by a Chinese
housewife and translated into English by a Russian schoolboy.

Years ago I was asked to do some product manuals for a company that
didn't exactly have a manual writer. I asked for a few examples of
current manuals. One I was handed was pretty bad, and I jokingly said
that it looked like it was written by a 20 year old exchange student
from Iran. Without smiling, the lady told me it had been written by
the designer, a 22-year-old exchange student from Turkey. She wasn't
kidding, she knew the guy.