Computer Power Supplies

[GeneticHeirloom]

I've noticed a lot of people using old power supplies and case fans to run their ventilation and I even had a friend build one for me back in the day.

I've got a conundrum I can't figure out and my tech geeks aren't really understanding what i'm asking of them (Cause I can't go into details with them lol)

So, I have 2 power supplies, 300watt, 350watt
I also have brand new 120mm Dynex case fan & 80mm Dynex case fan

My issue right now is getting the current from the power supply turned on and running to my fans.

The powersupply isn't connected to anything else but the 2 fans, and if I remember correctly from my last built model it had a switch that would turn the current on and off.

I do not have this switch, and surprise surprise the fans don't run when the power supply is plugged in (Even the built in powersupply fan doesn't turn on)

So my question is: What am I doing wrong and where can I get the piece to fix it?

 

[GeneticHeirloom]

Well I'm going to tear apart an old computer DC converter and put my fans on them.
If anyone has the link to which wires to cut and connect let me know.

 

[Aerohead]

You need to connect the green wire to any of the black wires.. This will make it think it's plugged into a motherboard and it will fire up.

 

[GeneticHeirloom]

Aero:

I'll check my power supply this evening, and if I find a green i'll connect it to a black i don't have connected to the PC Fan.

With the connection bridged, will just turning the power supply button on and off be able to run the fan?

 

[Corpsey]

this one has help me do it a few times....
http://www.icmag.com/ic/showthread.php?t=67482&highlight=power+supply

 

[10k]

Actually... if it's an ATX type power supply. You jump the green to the gray wire at the mobo connector and it will turn on the power supply. Yes, black will work, but the power supply is looking for the green to gray connection, simulating the power button of a computer case.

 

[Corpsey]

interesting, so if the black and green are already connected it should be cool?
ill note that for next time

 

[Kizzattack]

I didn't even have a green wire. I looked at the thread that yourcorpse suggested and connected the two wires that are where the green and grey should be (in the picture, in that thread), and it worked.

 

[GeneticHeirloom]

K+ to all you guys for showing me exactly what I was looking for and even more tips on if it's not exactly as shown.

You guys rock!

 

[headfortrinity]

It's a lot cleaner looking to get an old 12volt transformer from a thrift store. Something like a cordless phone power supply, they have boxes of them for cheap, maybe a dollar or two. Just make sure it's outputting 12volts and the correct amount of milliamps to run your fan cut and splice.

 

[GeneticHeirloom]

It's a lot cleaner looking to get an old 12volt transformer from a thrift store. Something like a cordless phone power supply, they have boxes of them for cheap, maybe a dollar or two. Just make sure it's outputting 12volts and the correct amount of milliamps to run your fan cut and splice.

I saw a couple threads on that, I like the idea, if the 2 power supplies turn out to be actually busted, i'll head over there and check out some adapter boxes.

 

[Kizzattack]

I saw a couple threads on that, I like the idea, if the 2 power supplies turn out to be actually busted, i'll head over there and check out some adapter boxes.

I know this is a few days old, but I thought I'd comment anyway. I found getting the right power supply for my fans to be a bit like looking for a needle in a haystack. If you can tolerate the size of the PSU, I recommend you keep it as you can connect many fans to it and not have to deal with fiddly adaptors and such. It entirely depends on circumstances though, and personal preference. I have personally found a PSU to just be easier and less hassle.

 

[toastfighter2]

Before I picked up my 120v axial fan, I used an adjustable dc voltage adapter(a wall wart) to power my fans. It went from 5v up to 14v with just a slide type switch, which meant that I could adjust the speed of the fans(it would power all three that I was using). I have also found that a lot of older cell phone chargers have enough juice to run a fan(the usb type will do it, but not great).

 

[blynx]

Actually... if it's an ATX type power supply. You jump the green to the gray wire at the mobo connector and it will turn on the power supply. Yes, black will work, but the power supply is looking for the green to gray connection, simulating the power button of a computer case.

Funny I had just pulled a power supply from an old computer the other week and saw that it didn't work by just plugging it in. I figured something had to be jumped, just didn't feel like looking up the info. Glad I stumbled across this thread. I just pulled it out again, jumped the green and grey, plugged it in and it worked great.

 

[Lord Doobie]

The problem using power supplies from computers is the fact that nobody's bothered to test the setup. They just use it.

What I mean by this is, yes...computer power supplies will power hundreds of computer fans. However, whether it's just the load being used or the full 300watts (or more) has yet to be determined. What we do know is that you're using at least 120v ac to power a PS which, in turn, powers a teeny fan.
You will need to contact a computer store, electrician, or electrical engineer to finally answer these questions.
"When I hook up only a fan to the PS, what's actually being used?"
"Which is more efficient to power a computer fan? A little DC converter that plugs into an AC outlet or a computer PS?"

 

[ScrubNinja]

What I mean by this is, yes...computer power supplies will power hundreds of computer fans. However, whether it's just the load being used or the full 300watts (or more) has yet to be determined.

It's only really using what the fans are using. Otherwise you'd see the 200 and whatever extra watts as heat or such.

 

[GeneticHeirloom]

The problem using power supplies from computers is the fact that nobody's bothered to test the setup. They just use it.

What I mean by this is, yes...computer power supplies will power hundreds of computer fans. However, whether it's just the load being used or the full 300watts (or more) has yet to be determined. What we do know is that you're using at least 120v ac to power a PS which, in turn, powers a teeny fan.
You will need to contact a computer store, electrician, or electrical engineer to finally answer these questions.
"When I hook up only a fan to the PS, what's actually being used?"
"Which is more efficient to power a computer fan? A little DC converter that plugs into an AC outlet or a computer PS?"

A PS is going to be less efficient simply due to the heat it produces, what the PS does that the other can't do is be found. I couldn't find one that could take the load from the 2 fans i have yet a 300 Watt PS will take a dozen more.

The PS is working great, I've got it on my mother cabinet. It is annoying having extra wires everywhere, but I can cut and clip any I dont want

 

[Corpsey]

yeah the only reason i used a PSU was that i had a couple laying around, so i couldn't just waste em'

 

[GeneticHeirloom]

Well, I found one issue with the PS, Turns out the actual fan that cools the PC does not turn on (tested on a 300 and 350 watt) even with the green wire connected to black... I'm thinking there's another series of wires in teh 20 pin that need to be connected to turn on the PS's internal fan.

 

[idontsmoke]

Well, I found one issue with the PS, Turns out the actual fan that cools the PC does not turn on (tested on a 300 and 350 watt) even with the green wire connected to black... I'm thinking there's another series of wires in teh 20 pin that need to be connected to turn on the PS's internal fan.

Is the fan that cools the PSU itself working?
If yes - your new FAN is dead or not poperly connected.
If no - PSU itself is dead or black and green wire are not connected.