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!

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
<p>Where does the Green wire connect inside the power supply</p>
<p>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 &quot;Remote&quot;.</p><p>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 &quot;Through Hole&quot; Labeled &quot;Remote&quot;, that's the Green +5V line. Hope that helps.</p>
<p>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?</p>
<p>Thanks Mate, I really appreciate your sharing</p>
<p>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?</p>
<p>its very nic and useful post ... and i made it and add images very soon</p>
<p>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:</p><p>-------------------------------------------------------------</p><p>Soldered:</p><p>- PSON (Green) -&gt; Ground (Black)</p><p>- 3.3VDCS (Brown) -&gt; 3.3v Rail (Orange)</p><p>-------------------------------------------------------------</p><p>Removed Wires:</p><p>- Blue &amp; Purple</p><p>-------------------------------------------------------------</p><p>I got all the same coloured wires and put them together, twisted them and Cable Tied the end to keep it neat.</p><p>-------------------------------------------------------------</p><p>Optional:</p><p>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.</p>
<p>This was incredibly useful. Thank you very much. </p>
<p>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.</p><p>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.</p>
<p>So, with no switch on my power supply, the shut down procedure would be:</p><p>1. Turn off connected devices.</p><p>2. Quickly unplug the power supply before the capacitors start to blow?</p><p>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..</p><p>Do I have this correct though?</p><p>The order on shutdown?</p><p>Just yank the plug?</p>
<p>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.</p>
<p>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. </p>
<p>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.</p>
<p>Thanks for the instructions. Saved me a lot of investigation and worked like a charm. Cheers!</p>
<p>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.</p>
<p>Great instructable. Simple. Easy to follow. </p>
<p>Very well explained. I will do it as you said with an additional switch. Thank you.</p>
<p>Thank you so much</p>
<p>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. -_-</p>
<p>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 :)</p>
<p>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.</p>
<p>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</p>
You missed something...<br>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
<p>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).</p>
<p>Would this work for running extra devices in a pc, ie 3tb SATA drive?</p>
<p>Thanks, man! Straight forward and simple. </p>
<p>Hello. I bought a gadget recently so i could turn a 3.5&quot; 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&quot; hdd and......There it is. All now is working great. Thank you very much......</p>
<p>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?</p>
<p>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.</p>
<p>Has anyone tried using a lighted rocker switch to control the power supply on lead instead of a regular switch?</p><p>The illuminated rocker switch has three leads- Power Ground ACCessory. </p>
Testing New strip led arrived!
<p>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.</p>
<p>Do I plug in the ATX before or after installing the wire into the green and black sockets?</p>
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.
<p>Very useful tip! Thanks!</p>
<p>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.</p><p>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.</p>
<p>Vielen dank! Ihr englisch ist sehr gut. Ich verstand, kein problem. </p>
<p>Quite simple ... i hope it will work because i tried a similar way but i blow up something!</p>
<p>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.</p>
<p>Thanks for this :)</p><p>At start I tried to use Power Good connection, that is shown on PSU - it didn't worked.</p>
<p>Nice job! Well done, and thanks, I was Google-ing this problem, and found your solution very helpful!.</p>
did that but make a weird noise and gives only 5v i need 12v now what?
<p>It needs a load to work correctly. Red wires are generally +5V, yellow wires are +12V.</p>
When I did this, mine briefly fires up and then shuts off on it's own. Any idea why?
<p>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.<br><br>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.</p>
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. <br> <br>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. <br>
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!
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.

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