I needed a power supply for an old AT motherboard based computer. All I had was an ATX power supply. You really can not purchase AT power supplies any more. Note: before starting on this project, make sure your ATX power supply supports -5vdc. Newer ATX power supplies are not required to support this. If not, this cable will not work.

Warning: Do this at your own risk. I will not be responsible for any issues. Make sure nothing is connected to electricity when doing this.(i,e. make sure everything is completely unconnected). If you do not, you will get electrocuted and die, so use common sense and be careful so you do not kill your working power supply and computer either. If you feel uncomfortable doing this, then get a professional to help you. Preferably you should not be color blind. You must know how to solder. Take your time making this cable.

To me the cable was not that hard to make but it did take a while. I also had to make sure of the safety precautions so no one or nothing was hurt and that I was accurate in connecting the wires..

Step 1: Whats Needed.

1 - ATX power supply
1 - AT Computer and monitor
1 - ATX to ATX cable Extension (Available a better computer stores)
1 - set AT wires (p8/p9) set from a dead AT power supply.
1 - Toggle On/Off switch (not a momentary switch).
Solder
Electrical Tape
Wiring diagrams for your ATX and AT power supplies. Yours may vary, so be careful. You may have to set up your own wiring conversion diagram. Mine is ONLY for the power supplies I used.

Tools
Wire cutters/strippers
Soldering Iron.

Step 2: What to Do.

1 Cut the ATX extension in half. Put the male end away as you will not need it.

2. Start striping ends and then start soldering wires per the diagram from the AT connectors to the female ATX connector and usually, but not always you will be soldering like colors together, (At least one set of the wires will not be the same color.) Follow the diagrams for your power supply.

3. At this point eight of the wires will be or should be un-connected. Now solder the switch to the power on and an extra black ground wire per the diagram.

4 Use electrical tape to cover any bare or exposed wires/ends or bare points on the switch.

5. Recheck wiring and of all is ok then use the electrical tape to bind everything up. (otherwise fix any problems so you do not fry your AT computer or ATX power supply.

Step 3: Use It.

Plug in the cable. (The AT cable end the black wires should be next to each other in the middle.) to the ATX power supply and the p9.p10 ends into the AT motherboard. Power it up. My cable worked fine. Can not promise it will work for everyone.

I am actually building a robot and I needed this cable for that to connect to a DC -DC ATX PS. The robot is priority one right now for us.

Step 4: It's a What?

Plan to start doing video’s for some of the things I do. Here is just a teaser. I did goof though and said “ATX” when I meant to say “AT interface on the motherboard.”

http://www.youtube.com/watch?v=JGaDABk-uJc

Step 5: Old Computer With New Life.

OPENBSD is a unix lookalike that is a cousin of linux. It is still supported, still free, and still works on older hardware. You can not say that about MSWindows XP, Vista, 7, and or 8. Excepting memory and cpu limitations, you should be able to run most software. It also comes with a default apache web server. It can be installed from floppy, cd or a network. Since you can use a gui (graphcal user interface), learning it makes it so easy per se to start using it. Why is everyone giving away old equipment when you can recycle it yourself. Makes the conversion cable even more valuable.