Can any one tell me how to effect a simple on/off control of a standard
ATX type power supply to use it on bench or for other projects? How
does motherboard control this function?
Thanks

"ee_design" wrote in message
ups.com...
Can any one tell me how to effect a simple on/off control of a standard
ATX type power supply to use it on bench or for other projects? How
does motherboard control this function?
Thanks

From the url below:

While we're at it, you can power up an ATX power supply by shorting the
green wire with any black ground wire. As you know, the ATX power supply
will not turn on normally without a motherboard connected to it. There are
times when you may want to test an ATX power supply or use the voltage from
one but don't really want to hook up a motherboard. There's only one green
wire and there are plenty of ground wires so it's easy to do. To use a bent
paper clip and insert one end in the green wire connector and bend it around
and put it into a black wire connector.

http://www.bluemax.net/techtips/ATXP...pplyWiring.htm

Also you usually need a load on the output of the supply before it will
start or stay on .

In article . com,
(known to some as ee_design) scribed...

Can any one tell me how to effect a simple on/off control of a standard
ATX type power supply to use it on bench or for other projects? How
does motherboard control this function?

It's usually a 'soft' logic switch. A momentary contact closure
toggles a flip-flop in the supply which turns it on. A continuous
closure of more than ten or so seconds usually turns it off.

With that said: Using a PC supply for any type of serious bench
work is a poor idea, IMO. They are often very (electrically) noisy, in
terms of RF emissions, their outputs are rarely variable, and most of
them need a minimum load on the +5V line to even regulate properly.

There are plenty of very decent and affordable 'lab' type variable
power supplies that show up at ham radio swap meets and electronic
surplus places, to say nothing of Greed-bay. If you're serious about
clean experiment power for your bench, or something noise-critical like
servicing radio equipment, you should seriously consider investing in
such.

Happy hunting.


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute
(Known to some as Bruce Lane, KC7GR)
http://www.bluefeathertech.com -- kyrrin a/t bluefeathertech d-o=t calm
"Salvadore Dali's computer has surreal ports..."

On Sun, 6 Aug 2006 09:06:15 -0700, Dr. Anton T. Squeegee
put finger to keyboard and composed:

In article . com,
(known to some as ee_design) scribed...

Can any one tell me how to effect a simple on/off control of a standard
ATX type power supply to use it on bench or for other projects? How
does motherboard control this function?

It's usually a 'soft' logic switch. A momentary contact closure
toggles a flip-flop in the supply which turns it on. A continuous
closure of more than ten or so seconds usually turns it off.

The logic is on the motherboard. The PS_ON signal is 'hard', ie there
is no flip-flop in the PSU.

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

for load you could use a light bulb 12v or a resistor
accross ground and 5vline 50-100ohm.
and a led on the power good se if it lights.

"ee_design" wrote in message
ups.com...
Can any one tell me how to effect a simple on/off control of a standard
ATX type power supply to use it on bench or for other projects? How
does motherboard control this function?
Thanks