Hi all!

I have an AT style PC Power supply. I used to use the entire computer it came from as a power supply simply tapping power from it (it was useless for anything else). This summer i had to move and threw the computer away only keeping the power supply to save space.

Now I want to start to use this PSU again, but I can not figure out how to start it. I've read at least 10 tutorials but none of them tells me what to do with the four wires the went to the power switch when the unit was installed in a computer. The colours are white, black, blue and brown. I suppose I want to short two of them to simulate me pressing the power button on the computer?

I hope my question was clear enough!

- David

An AT power supply or ATX? AT's generally stay on by themselves for an atx - jumper the plug as shown (red lines)

You can either short the wires or add a DPST switch.

The wires are:

Brown and Blue: Live and neutral feed wires coming from the 120v power cord to the power supply. When the power supply is plugged in, these will be HOT.

Black and White: These carry the AC feed back to the power supply when the switch is turned on.

Brown ------------->Black
............SWITCH.............
Blue --------------->White

When the switch is ON, Brown shorts to Black, Blue shorts to White.

Hope this helps.

Exactly what I was looking for, thanks a lot!

Now, where's my soldering iron

- David

Originally Posted by Andrew0820

Brown ------------->Black
............SWITCH.............
Blue --------------->White

When the switch is ON, Brown shorts to Black, Blue shorts to White.

Hope this helps.

Originally Posted by bergfalke4

Exactly what I was looking for, thanks a lot!

Now, where's my soldering iron

- David

Some AT PSU's need a load on the 5v to keep it going - a 10w auto lamp should do it.
Mike

It works! I had to put a 8 ohm 10 watt resistor between 5 volt and ground to increase and stabilise the voltage. I'm really happy, thanks for all advice!

- David

Originally Posted by bergfalke4

It works! I had to put a 8 ohm 10 watt resistor between 5 volt and ground to increase and stabilise the voltage. I'm really happy, thanks for all advice!

- David

good

this worked for me with an atx style psp

http://www.rcgroups.com/forums/showthread.php?t=368639

I have a Compaq supply, series PDP-115. I can't get it to start. It has a different plug from the one in the above post, two rows of 7 pins,Marked P1,a 4 pin marked P2, and then 2 4 Pin in series. It has 5v and 3v, but no 12v and the fan does not run. Does someone know how to start this one. Thanks Mike

Originally Posted by ImaBiggles

An AT power supply or ATX? AT's generally stay on by themselves for an atx - jumper the plug as shown (red lines)

i was only using ps_on (green) to ground and it worked perfectly...

I got the compaq to work and it will run my Apache 2500 OK. The green wire is +5v. I jumped it to the white wire and the +12v would come on but it would cycle on and off at about 1hz. Put a 10 ohm load on the 5v as some one suggested and the power supply is stable although the cooling fan does not run. Nothing got hot while I charged a 1300 2cell. I am happy and thanks to all on this thread.

Mike

Originally Posted by zbend

I got the compaq to work and it will run my Apache 2500 OK. The green wire is +5v. I jumped it to the white wire and the +12v would come on but it would cycle on and off at about 1hz. Put a 10 ohm load on the 5v as some one suggested and the power supply is stable although the cooling fan does not run. Nothing got hot while I charged a 1300 2cell. I am happy and thanks to all on this thread.

Mike

Glad we helped.
Mike

I always just plug an old hardrive into the PSU and it thinks it's up and running..