How To Turn On An ATX Power Supply Without A Motherboard
Reviewed by: d3bruts1d
Reviewed on: October 1, 2004
Guide by: Bryan McDaniel
Created on: October 1st, 2004
Price: Up To $15 USD (Or more if you have to buy a soldering iron)
Wether you need more power to run extra components, or you're just looking to test some things outside of your case, it's sometimes needed to turn on a power supply without having it connected to your system.
Today, I'll guide you through two different methods of accomplishing this, and believe it or not, both methods are extremely easy. :) Just keep in mind, that you will most likely void your warranty, and OverclockersClub (and especially me) take absolutely no responsibility for damage to your equipment or if you electrocute yourself.
As most of you probably know, you cannot simply plug in a PSU to the wall and turn it on. The PSU needs a connection to the motherboard to be told to turn on. When you press the power button on your case, it jumps the green wire to a ground, telling the PSU to turn on. When this “jump” is broken, the PSU shuts off.
The green wire on ATX plug is the “power on” line and is pin #14. The standard ATX plug will also have seven ground, or black wires.
Since we'll be going over two different ways, I've broken this down by Method 1 and Method 2. Since a PSU is pretty obvious, I'm not listing that.
- A piece of wire
- Wire Stripper / Knife
- Two Peaces of wire
- A Single Pole, Single Throw switch (SPST)
- Wire Stripper / Knife
- Optional Items:
- Solder Wick
- Soldering Iron
- Needle nose pliers
Getting it To Work – Method #1:
The first method, and the easiest, takes just a minute or two.
Before you begin, make sure your PSU is powered off and unplugged. Please keep in mind, that capacitors inside your PSU store enough current to kill (or at least make you feel uncomfortable). While we will not be working inside your PSU, keep safety in mind.
The first thing we want to do is to take a piece of wire, and strip off the coating on each end. Half an inch should be more than ample.
Now that the wire is stripped on each end, stick one end of the wire in the PSU's green wire connector, and the other end of the wire in any of the PSU's black connectors.
That's all there is to this method! The PSU can now be turned on or off using the power switch on the back of the PSU.
It is common for people to use paper-clips to jump the green and black wire in the same method as described above. While a paper clip will work, I highly discourage doing that.
Getting it To Work – Method #2:
Method #2 is a bit more in depth, cost more, but IMO is the better route to go. - Especially if you will be using this PSU inside your case to run a TEC, H2O setup, CCFLs, or other components.
For my system, I choose to solder the connections together on my switch, this is optional, but will help ensure a good connection.
As with Method #1, make sure your PSU is powered off and unplugged. Please keep in mind, that capacitors inside your PSU store enough current to kill (or at least make you feel uncomfortable). While we will not be working inside your PSU, keep safety in mind.
The first thing to do is to cut two pieces of wire to the length you need. Depending on how you will be situating this PSU and switch, your wire may only be a few inches or a few feet long. - For this project, I've actually used two different colored pieces of wire.
Next thing to do is to strip both pieces of wire on each end. Again, about half an inch should be enough.
Now, loop one end of each wire through one of the terminals on the switch. Needle nose pliers can be used to make a nice, tight loop around the terminals.
Optionally, you may chose to solder these connections in place. Make sure you are using a non-lead based solder to avoid lead poisoning. ;)
Now we need to connect the switch to the PSU. Simply plug one wire from the switch into the PSU's green connector and the other wire into any of the black connectors. It doesn't matter which one of the black connectors you use, and it doesn't matter which end of switch is connected to which wire. All that matters is that one wire is connected to green, and one is connected to black.
That's it, your PSU should now turn on or off simply by flipping the switch.
There you go, two simple methods to turning on your ATX power supply without having it connected to a motherboard. Being able to do this has been extremely helpful to me as a reviewer, however it also comes in handy if you run a high power Thermoelectric Cooler (aka TEC or pelt) that requires the use of a 2nd PSU.
There are a number of things you can do now to improve the look of the switch. Here's a few ideas:
- Mount the switch in a project box, or drive bay.
- Use a Military Style switch, suchs as the ones sold at FrozenCPU, SVC, Xoxide, or a number of other places.
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