Building a powersuply from an old computer psu

How hard would it be to add a low amperage 24V rail? I was thinking of a switch that would disconnect every other rail when ever you turned the 24V rail on. Max output is listed at 480 Watts.

I know that it's not arduino related, but it kinda is as this is to power my projects.

If im getting thhe description right id say it would be hard to modify the psu for 24 v versus whichever voltage it is at because it was entirely designed for the original voltage, you would have to redesign it and change watever necessary as fore disconnected rails either some mosfets or relays whould work

That's why I asked. I was thinking it would be as easy as a voltage doubler on a 12V rail, but then I started thinking about some of the stuff you were saying. I was just trying to think of things i could do to it just for the experience of it, but I don't want to spend my time building shit, either. As it turns out, there is plenty to do just converting a computer psu to a benchtop powersupply. I have made one of these before from a cigar box, but it was just hacked together quick and dirty. I used it for quite a while and it never let me down, but this one is gonna be pretty nice.

I have one more power supply question, though. What is the proper polarity for the power cord? I don't see anything about c14 and polarity. I know it's really the device that will mind or not, but I want it wired the way it's supposed to be.

I said no more power supply questions, but I do have a mystery. I was just going to use my meter and check the cord, then it would be easy enough to tell how the male part should be. When I put my test leads in the end of the cord it blew the 8a250V fuse. I switched the positive lead over to the 10A jack before I did that, I usually don't. I can't help but think that had something to do with it. I felt a buzz as soon as I got both probes in there and I immediately snatched them back out, but it was too late. The cord works fine powering a tattoo machine powersupply, so I doubt the cord is faulty. I have never had that happen to me. Any advice what I did wrong?

I found a potential polarity candidate. I'll see what any of you guys come up with before I say.

It sounds like you had the meter on measuring amps and you put it across a voltage and shorted the whole thing out.

If the psu has both a positive and negative 12v rail then you already got 24v, althought if one rail has less capabilities than that's what you have to go by, say 12v 1 amp and -12v 100ma, you can only draw 100ma at 24v