dual PSU's?

[Aero]

ok so I have been thinking about this for awhile for my old comp. I have a feww HDD's laying around and another PSU. I have a 200watt PSU and a few hdd's including one 250 gig that will blow either of my computers because I'm already pushing it. My question is how do I set up a second PSU so it will turn on when the other does? Do I have to add wires to the mobo connector? add another switch? what?

[OvRiDe]

I dont know if this would work or not, but theoretically couldnt you tap the green and black wires (I think those are the right ones) that are on the molex connected to the motherboard, and connect them to the corresponding green and black on the 2nd PSU?

[wingman358]

OvRide, I think that would work.

[Tommychu]

As long as both PSUs are physically attatched to the same case, you only need to tap the green wires. If not, you can either tap a black wire on the motherboard harness or link up any black wires from both PSUs without incident. Unless you're real stupid about it and break a ground on the motherboard harness; don't do that.

[onelegout]

A quick note; If you're running an old psu for the first time in a while, hook it up to a crappy old mobo and run it under controlled conditions and get ready to pull the plug just incase! I say this because I used an old psu today to test something, and suddenly there were a lot of sparks, a lot of smoke, and a small fire inside my psu. I fmanaged to pull the plug on it before it could turn into a big fire, but nevertheless I was very lucky that I didnt end up burning the house down! I opened up the psu to see what had cused it, and found a small scrap of metal melted to a coil of wire, and half the plastic melted inside, the tiny bit of metal had shorted something which had caused a spark, and this had caught 2 years worth of dust alight...
So yeah, test your old psus before you hook them up to anything expensive!!