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.

Remove these adsRemove these ads by Signing Up

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....
1-40 of 75Next »
IsaacV15 days ago

Thanks, man! Straight forward and simple.

KaneisK20 days ago

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......

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?

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.

willR261 month ago

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!1 month ago
Testing New strip led arrived!

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.

amywindsor2 months ago

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. -_-

sirtanly3 months ago

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

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.
angeloc25 months ago

Very useful tip! Thanks!

JoshB46 months ago

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.

gunterja6 months ago

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

Ahmedqatar8 months ago

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

cestmoi649 months ago

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.

lusis9871 year ago

Thanks for this :)

At start I tried to use Power Good connection, that is shown on PSU - it didn't worked.

Nice job! Well done, and thanks, I was Google-ing this problem, and found your solution very helpful!.

did that but make a weird noise and gives only 5v i need 12v now what?

It needs a load to work correctly. Red wires are generally +5V, yellow wires are +12V.

When I did this, mine briefly fires up and then shuts off on it's own. Any idea why?

A belated reply, but the power supply needs to see a load to stay on. It's being clever, noticing that there's nothing for it to power, and shutting itself off.

Per the comment above, a 5 watt load on the 5 volt side will probably keep it on. You could use a power resistor of the appropriate size.

cwagey3 years ago
The easiest thing to use to test a lot of devices that need a 'load' connected in order to operate, is a lightbulb. In this case, use 12volt automobile brake light bulbs, they don't cost much and they limit the current draw when they light up because the resistance of the filament increases.
Most may not power-up right off the bat.. they may power-on for 1/2 a second, then stop, if there is no load on the +5V.. this load can be 10-ohm,(10W) to 33-Ohm (5W).. Most ATA hard drives draw about 6-7W, dependent on the maker... (as long as nothing is connected to the IDE socket, powering up/down a hard drive will not delete data.) The switching circuitry will compensate on the load, maintaining the correct voltage.

A test I do, make the short to the PWR-on to GND as you describe. Plug the supply in to the wall. The cooling fan will power-up, If it needs a load, the fan will just go on for 1/2 a second, then spin-down. Unplug the supply from the wall.. Within 2 seconds, as the filter caps bleed-down, the cooling fan will spin-up again for only 1/2 a second. This is the switching circuit simply noticing no use load, and simply shutting down.
thanks amigo, I have an ATX power supply in English with labels for each color, and another what appears to be Japanese with no labels. The English ATX is just plug and use no questions asked, the other however i thought was scrap.You saved me from tearing it apart!
craig c5 years ago
If you have a DELL PSU instead of an ATX, theres a grey wire in the corner and a black one right next to it, just short them out instead of a green one to get same results.
Thank you ! I appreciated this info.
Working on a cnc machine, have a dell psu I'm using as the power supply.
arzola13 years ago
Thank you I needed this info
Vinsu4 years ago
Great! Had forgotten this. Now to make use of my spare PSUs...
FixedHDD (author)  Vinsu4 years ago
Glad you like this! You're welcome :)
cooler master rs 500, Why is this not working for me, the power supply was fine before i started this project. i jumped it once and it worked but now its not working for me...
They need a small load on at least one of their lines (12v/yellow, IIRC) or they cut out for safety reasons.
fjr_scoot3 years ago
Your English is better than most Americans! Thanks for a great instructable!
hore3 years ago
what devices, how about hair dryer, can i connect it with hair dryer..
FixedHDD (author)  hore3 years ago
and i thought hair dryers are going to be plugged in to the outlet.... But anyway, you can connet everything that works with 12V, 5V or 3.3V.
hore FixedHDD3 years ago
alright. thank u.
hore3 years ago
my questions can i connect wire(green one) like in the picture with soldering iron , will it work, or i just gonna blow something.
FixedHDD (author)  hore3 years ago
Soldering will be fine...
FixedHDD (author)  hore3 years ago
sure you can. Does your PSU have a switch? Well then it is no problem at all.

After all my work in this instructable I ended up with a PSU having two switches. You can spare one if you solder the green to the black wire.
hore FixedHDD3 years ago
how about power, what im trying to say is soldering iron might received more or higher voltage, could this possibly happen.
burekmaker3 years ago
I would like to know how to start ATX power supply without a PC with one button click and release (that the switch is not ON all the time like in this case, but only for a few moments when you press button - like when you press power button in PC when you want to start computer).. if you know what I mean.. tnx ;)
1-40 of 75Next »