I have this power supply we stripped out of a pc we're junking. It
has a 12V 10A section. I would like to use it as a 12V bench supply
for testing and running equipment. I have no plans for the other
supplies. Can I run it and the other supplies unloaded? And can I just
use the 12V supply without using the others? The unit presently won't
come on but there is a green wire in the bundle with the mother board
connector that I suspect needs some kind of proper bias on it but I'm
not sure. Does anyone have any information on this? Thanks, Lenny
Stein, Barlen Electronics.

" wrote:
I have this power supply we stripped out of a pc we're junking. It
has a 12V 10A section. I would like to use it as a 12V bench supply
for testing and running equipment. I have no plans for the other
supplies. Can I run it and the other supplies unloaded? And can I just
use the 12V supply without using the others? The unit presently won't
come on but there is a green wire in the bundle with the mother board
connector that I suspect needs some kind of proper bias on it but I'm
not sure. Does anyone have any information on this?

There are two kinds of PC power supplies. The original or "AT" supplies
which turn on and off by a switch and the newer ones called "ATX" which
turn on and off by the computer.

If the power plugs for the motherboard are seperate, you have an AT
supply, if they are one 20 or 24 pin plug, you have an ATX. Some have
both.

In order to turn on an ATX power supply, you need to short two leads on
the plug. This is well documented, STFW for "testing ATX power supply".

I have not done this with ATX supplies, but I have used AT supplies as
5 and 12 volt power supplies. Most of them require a load on the 5 volt
side, when I used one to power a 12 volt radio, I put an automobile tail
light bulb across the 5 volt leads. It drew enough current to keep the
supply active.

Note that while the DC voltage is quite clean, it is a switching power
supply and many of them have lots of RF noise on the DC leads. I had no
trouble using it for a VHF rig in a mixed HF/VHF environment, but many
people have complained about using them on HF rigs.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

wrote in message
ps.com...
I have this power supply we stripped out of a pc we're junking. It
has a 12V 10A section. I would like to use it as a 12V bench supply
for testing and running equipment. I have no plans for the other
supplies. Can I run it and the other supplies unloaded? And can I just
use the 12V supply without using the others? The unit presently won't
come on but there is a green wire in the bundle with the mother board
connector that I suspect needs some kind of proper bias on it but I'm
not sure. Does anyone have any information on this? Thanks, Lenny
Stein, Barlen Electronics.


Look up ATX pinout and you should find the info you need to fire it up.
Connect the power on wire to the standby wire and that should do it.

On most you'll need to load the primary output before the secondary outputs
will regulate. On old AT PSUs it was the 5V, but on yours it's probably the
3.3V output. A power resistor or automotive lightbulb will work.

" hath
wroth:

I have this power supply we stripped out of a pc we're junking. It
has a 12V 10A section. I would like to use it as a 12V bench supply
for testing and running equipment.

It's amazing what you can find with Google:
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply
http://www.instructables.com/id/ATX--%3E-Lab-Bench-Power-Supply-Conversion/
http://www.fivemanconspiracy.com/?q=node/32
http://www.makezine.com/blog/archive/2005/12/how_to_convert_a_computer_atx.html
http://www.makezine.com/blog/archive/2005/12/how_to_atx_lab_bench_power_sup.html


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Oct 27, 4:35 pm, Jeff Liebermann wrote:
" hath
wroth:

I have this power supply we stripped out of a pc we're junking. It
has a 12V 10A section. I would like to use it as a 12V bench supply
for testing and running equipment.

It's amazing what you can find with Google:
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-P...
http://www.instructables.com/id/ATX--%3E-Lab-Bench-Power-Supply-Conve...
http://www.fivemanconspiracy.com/?q=node/32
http://www.makezine.com/blog/archive/2005/12/how_to_convert_a_compute...
http://www.makezine.com/blog/archive/2005/12/how_to_atx_lab_bench_pow...

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Thanks a lot for finding this for me! I really appreciate it. Lenny.

On Sat, 27 Oct 2007 19:50:21 GMT, "James Sweet"
put finger to keyboard and composed:


wrote in message
ups.com...
I have this power supply we stripped out of a pc we're junking. It
has a 12V 10A section. I would like to use it as a 12V bench supply
for testing and running equipment. I have no plans for the other
supplies. Can I run it and the other supplies unloaded? And can I just
use the 12V supply without using the others? The unit presently won't
come on but there is a green wire in the bundle with the mother board
connector that I suspect needs some kind of proper bias on it but I'm
not sure. Does anyone have any information on this? Thanks, Lenny
Stein, Barlen Electronics.


Look up ATX pinout and you should find the info you need to fire it up.
Connect the power on wire to the standby wire and that should do it.

No, connect PS_ON* to any ground wire.

See http://pinouts.ru/Power/atxpower_pinout.shtml

On most you'll need to load the primary output before the secondary outputs
will regulate. On old AT PSUs it was the 5V, but on yours it's probably the
3.3V output. A power resistor or automotive lightbulb will work.

IME most PC PSUs regulate by sensing a weighted average of the +5V and
+12V rails.

I believe this example is typical:
http://www.pavouk.org/hw/en_atxps.html

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Sat, 27 Oct 2007 14:52:10 -0700, "
put finger to keyboard and composed:

On Oct 27, 4:35 pm, Jeff Liebermann wrote:
" hath
wroth:

I have this power supply we stripped out of a pc we're junking. It
has a 12V 10A section. I would like to use it as a 12V bench supply
for testing and running equipment.

It's amazing what you can find with Google:
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-P...
http://www.instructables.com/id/ATX--%3E-Lab-Bench-Power-Supply-Conve...
http://www.fivemanconspiracy.com/?q=node/32
http://www.makezine.com/blog/archive/2005/12/how_to_convert_a_compute...
http://www.makezine.com/blog/archive/2005/12/how_to_atx_lab_bench_pow...

--
Jeff Liebermann

Thanks a lot for finding this for me! I really appreciate it. Lenny.

You can convert your AT or ATX PSU to a tightly regulated 13.8V supply
by changing the +12V sense resistor and removing the +5V sense
resistor. You may also need to modify the overvoltage sense zeners, or
whatever circuit is used to monitor this condition.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.