Use a Compaq 200 Watt Power Supply (PSU) as a second power source

As you can read I recycle all my old hardware and the time has come that my power supply of 200 Watt cannot provide enough power for my backup server.

I have lots of Compaq power supply's laying around, so I figured to use one of these PSU's. I tried to search on the internet for solutions to hotwire the power supply. The message I found in google was: "Connect the Green wire (PSON) with any black wire (Ground)".
Of course Compaq figured to use a non standard way, and nobody bothered to document this, so now I have done so. I hope you find this helpful!

Be AWARE, you can get a shock, so watch your fingers!!! Also these steps can burnout your power supply or any devices you connect to the Power Supply Unit (You are warned)

Okay, disconnect all the wires from the Compaq Power supply (Model: 221256-001) and since you will probably toss away the Compaq deskpro EN, be good to your environment -- recycle that thing.

Get a cheap cdrom, hdd that you can connect to one of the molex connectors so you have a minimum load on your power supply, or else the PSU will not do anything.

Plug in the power from the wall into your seperate power supply, and watch your fingers! Get the 24 pins Motherboard connector and look at the wires. First connect the Grey Wire to any brown wire (Use one of the thick wires not the thin wire!) on the connector with a paperclip (Just bend it into the right shape). Check your Power supply for funky smells, if not all goes well!!

 Connect the grey sense wire to a brown wire
Now connect the green wire to the white wire and the fan should be spinning.

 short the white wire to the green PSON wire
Check your dummy device to create a minimum load for your power source, does the drawer open close, are the led's on? If there is no led on the device itself, you can connect a led between a red wire and a black wire.
If all works okay you know you have 5 volt and 12 volt.

Here are the colors and the descriptions I know so far:

brown:  	+3.3V
                      black:    	Ground (0)
                      red:       	+5 V
                      grey:     	Power OK (To check if the power is ok)
                      purple:  	+5 volt Standby Power (Only for very low power consumption)
                      blue:      	-12 Volt
                      green:  	PSON (Short this to white wire to jump start your Compaq PSU)
                      yellow:		+12 Volt

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I have found these sources, but as you can see the colors do not match totally:

To fully check the voltages use a Multi-meter. Check if the multi-meter works correctly, I know mine gives 3 volts too much on the display.

Remember that you first must connect the grey to the brown wire and as a second step connect the green wire with the white wire.

Good practice would be to solder a wire between the grey cable and a brown cable, and then putting a flip switch between the green and the white wire.

Here is an example of how I did it, cut the grey and a thick brown wire loose and solder them together.

 Solder the grey and brown wire together
Don't forget the tape these wires of or they will short on your computer frame.

I have used an old flip switch, and check if it's still working, on the white and green wire.

 Solder the white and green wire to an flip switch
Stay safe and always disconnect the power before soldering the wires!

Comments (1)


The article is ready, i double checked it on grammer and spelling, but i'am dutch so be gentle! ;-)

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