Introduction: How to Power Up an ATX Power Supply Without a PC!

Picture of How to Power Up an ATX Power Supply Without a PC!

In this instructable i will show you how to power up an ATX Power Supply without a PC.

Maybe in some cases you want to test an old CD-Rom Drive or something else.
All that you have is a PSU from an old PC an a wire.

Here I show you how do to it.

Step 1: Search!

Picture of Search!

Just look after the green wire in the cable tree from the PSU.
Follow it to the 20 or 24pin ATX plug.

The green cable is in a way the "reciever" you need to power up the PSU

Step 2: Connect!

Picture of Connect!

Now it's time for the wire.
Bend the wire and close up the little green plug from the big ATX plug to any other BLACK plug. Cause the black is the ground. To come off best you should connect the green with black besides the green.

Your PSU should power up immendiatly!
You are done!

2 Notes:

Use a thicker cabel for this. a standart one will cause a loose connection witch
isn't good for the PSU.

When you do this make sure that you have some device(s) connected to the PSU. Otherwise your PSU tries to drive the non-existing device an will overheat.

Step 3: Extra Options

Picture of Extra Options

Add a switch instead the wire!

simply bend 2 wires like I do in the pictures an stick them into the black and the green port of the ATX plug and the other ends into the switch.

Ready to go!

BTW: I'm German. Maybe my English isn't so good....


EdwinM73 (author)2017-08-31

You missed something important for 24 pin PSU,s. i bet many had tried this and had their PSU just turn on for a second then turn off, If you have a 24 pin psu you MUST connect the brown cable to an orange cable "brown is the voltage sense" and the green to black ! Your 24 pin psu will now work as intended standing alone. Additionally for stable and correct voltage you should also have your psu under 10% of its rated load from startup, i.e. if you have a 750watt psu you should have 75 watts of load minimum, you can just use a Panel Mount Fixed Resistor say 50 to 100 watts, again the psu will turn on with out load but may not give the exact voltages you desire. Hope i helped you all : )

jleebiz (author)EdwinM732017-10-31

Hi Edwin,

I am also running into the same problem and landed on your response here in regards to connecting the brown to an orange connector. So I have tried this, and still the PSU will turn off as soon as I put load on the 12v 4pin connectors. One thing different though is that my pin #13, is actually brown and orange. There is two wires going to the pin. What does this mean? Does this work differently?

godelievefranssen (author)2017-09-21

Hey everyone,

I followed this guide and connected my Arduino on the 5V and a 12V small motor on the 12V. This worked perfectly, but when I tried to connect a bigger motor (a windshield wiper motor) to my ATX, it didn't work. The ATX generates about 22 amps so it should be working! Does anyone know how this is possible?

Thank you!

chathurangadesilva (author)2017-06-30

So after doing this, is it possible to run a hard disk (old 4pin socket HDD ) continuously by plugging it to the power supply, so that I can use it as a make-shift grinder ?

Tried it, the HDD runs for few seconds and stops.

WaqasB1 (author)2017-04-21

Please help me!! When I connect black with green. It starts with a jerk and then turns off.. What is wrong with that ?

AdamS504 (author)WaqasB12017-05-31

or do a google your power suppy followed by 24 pin pinout

AdamS504 (author)WaqasB12017-05-31

are u using a button looks like u need a switch or just wire so try a switch itll probally work tho dunno what else to say

I have the same problem, you already fix there?

I use an ATX by Cooler Master (V1000)

Thank you!

zolv made it! (author)2017-04-21

I made it when I fixed my ATX PSU.

peppermanron (author)2016-09-16

Where does the Green wire connect inside the power supply

JeffJ100 (author)peppermanron2017-03-19

If you haven't found your answer yet, (this is a couple month old question...), on my ATX Power block, most of the cables are labeled with the Voltage (on the board itself), However, the green wire is, at least on mine labeled "Remote".

If you've figured it out just disregard my mssg, but if you have yet to find an answer, look on the board for a "Through Hole" Labeled "Remote", that's the Green +5V line. Hope that helps.

NatN4 (author)2017-03-09

i am planning to use this in my pc. is it okay to power a hard drive using this? because i will connect two psus to an avr, so when i switched the avr on, the wired psu will turn on. will it be okay that the hard drive is powered while the motherboard is not?

jimburnsinc (author)2016-12-28

Thanks Mate, I really appreciate your sharing

peppermanron (author)2016-09-16

Without looking at any vids or other I had the idea of using the power supply from an old PC. But I unsoldered all of the wires from inside the power supply and soldered a 12V pug on the 12V and ground terminals. but it does not work. So Ithink i need to solder a wire from wherever the green wire connects to ground inside the power supply. Can you help?

tojihi (author)2016-07-28

its very nic and useful post ... and i made it and add images very soon

OC--K1NG (author)2016-07-26

This is a fine way of doing it, I went with the soldering method of modding as I have a switch on the back of the PSU. I did the following:



- PSON (Green) -> Ground (Black)

- 3.3VDCS (Brown) -> 3.3v Rail (Orange)


Removed Wires:

- Blue & Purple


I got all the same coloured wires and put them together, twisted them and Cable Tied the end to keep it neat.



Instead of removing the 5VSB (5v Standby (Blue Wire)) you could put an LED positive led to this, and the negitive leg of the LED going to Ground (Black) through a resistor (for current Limiting). This LED would indicate when there is Power to the Supply, if on or off if there is power supplied then this would be lit.

BibiM2 (author)2016-07-07

This was incredibly useful. Thank you very much.

ruggb (author)2016-05-21

This is the whole story. A long time ago it was true that to get 12V from an AT PSU you had to have a load on the 5V. This is no longer the case unless the PSU is VERY old. Some PSUs have a power SW on the back, some do not. Again, a long tine ago none of them did because the power sw was hard wired to the front panel. It doesn't work that way any more. The units with a SW on the back just have that as a feature.

The unit is powered on with a momentary push button sw on the front panel. This sw goes to a ckt on the MB (powered by the 5V that is on all the time unless you turn the main sw off or pull the plug). That ckt latches the green wire connection to ground - the same as what you do with the short from green to black. SO--if the PSU does not power on in the unit, it could be an open wire to the front panel push button (most common) or it could be the ckt on the MB. It is easy to get the wires from the push button on the wrong terminals on the MB.

TomC12 (author)2015-04-16

So, with no switch on my power supply, the shut down procedure would be:

1. Turn off connected devices.

2. Quickly unplug the power supply before the capacitors start to blow?

It occurred to me that it's probably pretty toasty in there and it would make sense to let the fan cool things off before pulling the plug. But I suddenly remembered what was said about the capacitors not having a load to determine..

Do I have this correct though?

The order on shutdown?

Just yank the plug?

JamesR133 (author)TomC122015-12-29

What are you talking about? This is basically what a mobo does (It keeps these two pins shorted while it's on). No caps will blow if you do this and don't put any load on the psu. By that logic a faulty mobo would get PSU to blow up. Also, every psu has a main switch on the back, no need to jank the plug, even if you just short these pins with a wire ... Just thought I'd let you know.

ruggb (author)JamesR1332016-01-17

Well, not EVERY PSU has a mechanical power sw on the back. Older Dell PSUs may be proprietary so check model. Older PSUs (very old) may require a load on the +5V to produce 12V.

JamesR133 (author)ruggb2016-05-04

I have never seen a PSU without a power switch before. Only PSU that didn't have a power switch on the back were AT and these were turned on by a wired remote switch that usualy went on the front of the tower.

DanielN129 made it! (author)2016-04-24

Thanks for the instructions. Saved me a lot of investigation and worked like a charm. Cheers!

BrentNewhall made it! (author)2016-04-16

Thank you so much for this! Really useful. I just ran a wire between one green port and one black port, and the power supply works like a champ.

Dave85 (author)2015-11-23

Great instructable. Simple. Easy to follow.

arcespre (author)2015-10-23

Very well explained. I will do it as you said with an additional switch. Thank you.

meeravali (author)2015-10-13

Thank you so much

amywindsor (author)2015-01-10

Thank you so much! I thought my new PSU was DOA until I tried your trick and it fired right up. Of course, now I have to figure out what I did wrong somewhere else in my wiring. -_-

wb7ptr (author)amywindsor2015-09-20

The motherboard in the computer might have a problem rather than the power supply. I had that happen one time and thought the power supply died. It was fine but the motherboard had died on me. Put a new one in and the power supply was great. Those power supplies have some kind of circuit in them to tell when they're connected to something and if that circuit goes bad, looks just like it died on you. I'm going to rig one of those to run my ham radio station :)

TSengN (author)2015-06-27

CutterSlade made it! (author)2015-05-20

Needed more amps for charging my LiPo batteries than my lab PSU could deliver. So I tried my old PC PSU and now I can charge @ 3 A instead of 2 A.

TeriD1 (author)2015-04-26

wow so my old brain says add a switch use my old 300w power supply attach it to the hdd grinder and I have a portable grinder....awesome will post pictures when it is done

hman123467 (author)2015-04-18

You missed something...
Put a 5v led from the power OK to a black wire (I think) and it should start. If you are having trouble try that

TomC12 (author)2015-04-16

Great tutorial by the way. This seems to have worked for me, not having an on switch on the power supply, I could not start it. But your video helped. Lights are running off of it. Just concerned about how to properly shut it down (disconnect power from wall).

Bubbleblower (author)2015-04-03

Would this work for running extra devices in a pc, ie 3tb SATA drive?

IsaacV1 (author)2015-03-26

Thanks, man! Straight forward and simple.

KaneisK (author)2015-03-11

Hello. I bought a gadget recently so i could turn a 3.5" sata hdd disk to usb disk. But i couldn't power the disk. I happened to see your page so i tried with an old psu that i wasn't using...I was dissapointed at first because the psu started for a moment and then it stopped. Couldn't read the disk. But then i remembered i had an old cheap desktop fan that could be powered by molex. So i connected both the fan and the 3.5" hdd and......There it is. All now is working great. Thank you very much......

pablo.marroquin.5811 (author)2015-03-09

Hey FixedHDD I don't know if you're still answering to comments on this instructable, but I'm wondering, I have this PSU that seems to be the issue of why my pc is not working, however, I tested the voltage from the green wire and I do get 5v, but nothing happens when I short it, do you think it's fixable/worth it?

michael.park.5243817 (author)2015-02-26

Wow! FixedHDD really created a classic here. Concise, easy to understand and with pictures that really help. Six years and over a quarter million views later and it is still helping people. And it did help me. Just what I wanted to know explained in clear English. Fixed HDD probably isn't even monitoring this any more but I send him (or her) my thanks from California. Also thanks to the German schools for teaching English so well.

willR26 (author)2015-02-06

Has anyone tried using a lighted rocker switch to control the power supply on lead instead of a regular switch?

The illuminated rocker switch has three leads- Power Ground ACCessory.

Qtronik made it! (author)2015-02-05

Testing New strip led arrived!

joey.anderman.9 (author)2015-02-04

I used this to power a couple of PC fans to cool my entertainment center. I had an issue with my cable box and home theater receiver overheating. I could not keep the front doors open because I have a toddler running around that likes to push buttons on everything. This saved my equipment.

sirtanly (author)2014-12-19

Do I plug in the ATX before or after installing the wire into the green and black sockets?

bmartinez19 (author)sirtanly2014-12-30

Unless the part of the wire you are touching is insulated, or you wired up a switch, I'd plug it in AFTER you make the connection. The amperage probably isn't enough to cause too much harm if you shock yourself there, but I'd be better safe than sorry.

angico (author)2014-10-13

Very useful tip! Thanks!

JoshB4 (author)2014-09-26

Thank you for your tutorial. I appreciated it very much. In a week or so, I'll be buying a PCIE to Thunderbolt enclosure and a graphics card for which I'll need a separate power supply. I'll be using a power supply from an old PC to power the graphics card because the enclosure only supplies 25 watts, which is probably why Intel approved it(25 watts isn't enough for a graphics card). I tried the power supply and it didn't work. Now that I've found(and read) your tutorial, I'll be able to make the power supply function so it'll power the graphics card.

Regarding your English, I agree with Gunterja, your English is very good, and I'm a very tough grader. To me, incorrect grammar and spelling is mentally painful. Aside from a few capitalization mistakes and one spelling mistake, your English spelling is also quite good, and is better than that of a significant number of Americans.

gunterja (author)2014-09-04

Vielen dank! Ihr englisch ist sehr gut. Ich verstand, kein problem.

Ahmedqatar (author)2014-08-01

Quite simple ... i hope it will work because i tried a similar way but i blow up something!

cestmoi64 (author)2014-06-23

First few times I tried this I had some nice explosions (I suspect I blew a few capacitors). But running a couple fans for me now. (Presumably it would no longer work as a computer PSU now but it seems to do the trick) and as there are no more pops I presume i've got no capacitors left to blow now.

About This Instructable




More by FixedHDD:How to upgrade the optical drive from your Powermac G4 Quicksilver 2001/2002How to power up an ATX Power Supply without a PC!
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