pc power supply

[FLPilot]

Can anyone describe to me how to make a pc power supply work without having to connecte it to a motherboard? Is it just a matter of crossing some wires to make a connection? Or is this something more complex?

 

[Sebi]

Just make a shortcut between PS-ON and GND, but keep in mind: for proper work need a minimum load on +5V output (about 0.5..1A).

 

[FLPilot]

Thanks Sebi,

I'll take a look when I get home. I appreciate your quick response.

 

[FLPilot]

I looked at my power supply and it has a connection with the following pinout:

1. Power Good * Orange
2. +5Vdc Red
3. +12Vdc Yellow
4. -12Vdc Blue
5. Ground Black
6. Ground Black

7. Ground Black
8. Ground Black
9. -5Vdc White
10. +5Vdc Red
11. +5Vdc Red
12. +5Vdc Red

so what would I short? #1 ???

 

[checkmate]

You are using an old AT PSU. AT PSUs are activated via AC switches. Don't fool around with AC if you are not famliar with them.

 

[Nigel Goodwin]

At old AT power supply doesn't need a switching signal, it comes on as soon as you apply power. As with the ATX one, you should have a permanent load on the 5V rail for it to work properly.

 

[evandude]

go to radio shack, and grab yourself a 10 ohm 10 watt power resistor. Stick that across the 5v line and you will be all set. I have been using an AT power supply as my benchtop supply for years now that way.

 

[FLPilot]

Thanks everybody for your replies.

 

[samcheetah]

what does the +5VSB (purple) wire do???

does it just supply normal 5V like the red wires do? if yes, then why is it different from the red wires?

 

[Optikon]

what does the +5VSB (purple) wire do???

does it just supply normal 5V like the red wires do? if yes, then why is it different from the red wires?

If I recall, +5VSB is 5V stand-by which can be used for lower power circuits in the event that 5V is not ramped up yet, or short circuit fault.
It cannot source as much as main +5V, I think of order of 100mA or so..

 

[Sebi]

Yes, this is a standby +5V for a section of motherboard. The ATX types contains two independent PSU, one for standby (always work when plugged in), and the main PSU. So possible wake-up the PC via LAN-card, from kbd,etc.

 

[samcheetah]

okay thanx

actually i have been using an old switching PSU salvaged from a computer as a general purpose power supply. i havent used any permanent load. but now ill go with evandude's suggestion.