Hey guys i just wrote this guide for fusionmods.net and i figured i would post it on here as well. If anyone else wants to repost it on their site, just leave credit or a link back to my place is all i ask :P
This guide will explain how to have two power supplies turn on and off together while attached to one motherboard.
This will require some very simple wiring, and as such some basic tools and supplies are needed.
- Soldering iron
- Some sort of molex connectors (I got mine in the auto section of walmart)
- Heatshrink or electrical tape
I’d like to say that I started this guide because I’ve just recently replaced my secondary PSU after it died of old age. It went peacefully into the night.
Here’s a shot comparing the two.
- the one that died was a 400w PSU that is a bit over 3 years. The new one with the nice black finish is 550w. And while I don’t need as much power since I’m running two PSU’s this one was at an awfully nice price.
The first task is to locate the 14th wire, this will be the only Green wire on the P1 connector (the one that powers the motherboard). Then along with any black wire since we need a ground, cut them in half at about the same lengths. Once that is done, strip the ends, leaving around a half inch.
Now take your molex connector, matching which side will connect to the ground and which to the power, give them a quick twist. Before you fix the other end of the ground and power, slide about an inch length of heatshrink over the ground and power wires. Now find the other side of the corresponding wires and twist them all together.
Once this is finished, grab your soldering iron and solder and using your best judgment, get enough on there to hold them together for life
Your results should look very similar to this (sorry about the blurry pic, this is the best I was able to do.)
Now slide the heatshrink over the bare spots in the wiring. To affix it, many people use a lighter, if you do this, just be careful not to singe the heatshrink. I ended up using a heat gun which is for the most part an over-glorified hair dryer, but I wont have to worry about singing anything with it.
Once you repeat this process with your other power supply your ready to roll. Because we wired them this way, once your two power supplies are connected together either one can be the primary one. All you have to do is plug the P1 connector into the mother board and BAM, your set.
Heres a few spiffy pics of what you might want to expect,
- this is my case with both power supplies mounted
- This is the custom back panel I made to mount the second PSU, not to big on appearances but I can deal with that.
- And finally this is a good reason to have a second PSU. I have 4 CD-Roms and two hard drives in there.
* A good practice on Dual PSU’s is to have one power all the critical components, MOBO, Harddrives, and the other all the seconday components like CD-Roms, Floppy, Ect. Now of course you’ll want to balance the consumption between them, but this is just a suggestion in the event that one does die one day, it shouldn’t do any real damage by shutting off.
** And on a final note, if you want to make a great test PSU with a hard on/off like the old AT ones, just put a jumper in pin 14 (the green wire), and connect it to any ground. Once you do this, the power button on the back of the PSU will function as the on/off switch.
I hope you all found this worth while, question or comments are always welcomed.