Instructables

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.

 
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Step 2: 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.

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Ahmedqatar28 days ago

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

cestmoi642 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.

lusis9875 months 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.
arzola12 years ago
Thank you I needed this info
Vinsu3 years ago
Great! Had forgotten this. Now to make use of my spare PSUs...
FixedHDD (author)  Vinsu3 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_scoot2 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 ;)
FixedHDD (author)  burekmaker3 years ago
Well, to keep the PSU up and running the green and the black wire must be shorten permanently. A pulse switch doesn't work.

Buf if you are familiar with working with relays and stuff you could do this.
Nice work mate :)

I've been looking for a simple way of getting my PSU to work without a motherboard, and it doesn't get much simpler than this!

Thanks.
vectorges3 years ago
I have converted two ATX supplies (successfully) to power lights in my kitchen. Now I have two more that don't power up. I shorted the green wires. I put a 10w 10ohm resistor between a red and black. I did something with the purple. Any other suggestions?
FixedHDD (author)  vectorges3 years ago
What did you with the purple one? The purple one is the 5V+ Standby Voltage, the current, witch powers the RAM during standby (otherwise the data stored in the RAM would be lost)

Don't mess with other wires instead of green and black (will power up the PSU like i wrote) and orange, red and yellow for the currents 3.3, 5 and 12 volt.
jj.inc3 years ago
I need to know what I am missing because don't more companies than ATX make power supplies, like mine is a NZXT
FixedHDD (author)  jj.inc3 years ago
I think I don't understand that properly... ATX is not a company its an industry standard for PC power supplies. Any PSU that you can buy today is a ATX pwer supply.
jj.inc FixedHDD3 years ago
,but ATX still has standards for things like motherboards
jj.inc FixedHDD3 years ago
aaa, ok, thanks
robbe473 years ago
goede instruktable heb zelf drie pouwer boxs geprobeert het werkt uitsteken --dikke draat zware schakelaar en klaar
Solderguy3 years ago
Wow. Thank you so much for this instructable. I can now transform my old power supply into an awesome bench power supply!
rayyashi4 years ago
Thanks for your info i'v been looking it up to see how it can power hid xenon 35w thanks would you please show where to put a resistor or does led on 5v do the trick?
FixedHDD (author)  rayyashi4 years ago
i think an LED would do the job too!
srilyk4 years ago
 Excellent, simple, clear instructable. Great job!
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