Introduction: How to Turn on a Computer Power Supply Without a Computer

Computer powers supplies are readily available and make a good 12 volt or 5 volt power supply. The only thing is when they are not connected to a computer you need a way to turn them on. It's really very simple. This is an ATX Power Supply for a typical modern computer.

Step 1: Jumping Pins

Looking down on the main ATX connector with the locking tab facing up. Jump the green and black wire, they are the pins 3 and 4 counting from the right.

I spliced and soldered in a switch to make it convenient to turn on and off.

Step 2: Video of the Process

Here is a video of the process for those who like to view it.


ThomasK19 (author)2016-02-15

I will soon have the need to use a PC power supply. Could you state what type of supply you're using? Is it ATX?

I read somewhere that for ATX you need a dummy resistor (or a 12V lamp) to draw some minimum current to keep it up and running.

ronanry (author)2016-02-15

2 things :

1.Shouldn't your switch be a "pushbutton" switch (the one with the spring, that make it come back in place) and not a "constant contact" one (sorry i'm hard to understand, i don't know the english term for these 2)

2. When you use a power supply, check your need and the power used ... not need to use a 650W power supply only to use the 5V ...

MaxPower1977 (author)ronanry2016-02-15

A momentary switch (push button) will not keep the power supply on, in a computer motherboard there is circuitry that keep the power supply on. The "jumper" between the two wires must be constant for the power supply to remain on. So it is necessary to have a switch on the whole time.