Dual PSU's?

[quakefiend420]

ok, i have a box i just built with a lot of scsi drives in it...the original psu doesn't have enough juice on the 12v rail to handle that many drives, so i added a second psu just to power the drives...my question is, how do i turn the second psu on with the first when i power on the system?

i seem to remember hearing something along the lines of shorting the green wire in the 20pin connector to black(ground) but i'm not sure and don't wanna fry something

thx in advance

 

[So]

I BELIEVE (haven't actually done it) that you SHOULD be able to wire the GREEN/Black ires to the power switch on the case, in parallel to the wire on the mobo, which should turn the second PSU on when the power button is pressed.

 

[quakefiend420]

ttt

 

[CZroe]

My CoolerMaster CMStacker holds two PSUs and the power switch operates both of them. There is a short ATX "Extention cable" that goes between the primary PSU and the motherboard. Two wires go from it to another ATX connector that has no other pins. You plug the second PSU into it and it fires up along witht he first. I'm sure they sell these somewhere.

Anyway, after unplugging everything oneday, I noticed something weird: If I plugged in the second PSU, which is only connected to drives, it comes on by itself! fans, drives, everything. If I then plug in the main PSU, it immediately shuts off until I push the power button. It may be because I have so much draw on the PSU that my equipment is acting like a load resistor!

 

[quakefiend420]

bump

 

[YOyoYOhowsDAjello]

Crazy Night Crew...

Yeah, So is right on the shorting the green and black wires on the PSU. I've seen several guides and that's what they all say.

You could also do what I had done before and if you have an old AT psu around, it will have a power switch as one of the cables coming out of the PSU. Just hit the switch and it'll fire right up with nothing attached.

 

[Some1ne]

You could always just short the second PSU, and leave the drives perpetually powered on. They'd actually last longer that way.

Or, in theory you could yank wires 14 and 17 from the second PSU, and splice them with wires 14 and 17 on the first, and then hitting the switch should power them both on (although don't take my word on this, EE is not my forte, and like I said, "in theory").

 

[Fullmetal Chocobo]

Okay, this is wht you have to do. The green wire is the key--when shorted to a ground wire (black one), the PSU comes on. So the best thing to do is to get an extender for your 24p or 20p connector (so that you don't have to damage the original PSU wiring), and cut the green, and wire in a switch. I actually cut them before they go into the connector, because I didn't think about using a extender.

If you need pics or something, let me know. I have a 660w and 460w Enermax in my machine, and I was pretty much in the same boat you are in. Now I'm trying to figure out exactly how many hard drives, fans, and lights the second PSU can handle. Yeehah...

Just FYI: Go down to "Tas" on the site in my machine to get general pics of my machine...
Tas.

 

[quakefiend420]

cool it works

thx guys

btw this thing sounds badass when 6 drives spin up at once...although i'm sure it'll get annoying really quickly