Entertainment Center Mod & Airflow (stand-alone PSU w/ fans)

I am rookie at wiring, and I cannot find information on any forum about case fans & PSUs running as a stand-alone system (w/o a motherboard).

I am trying to improve circulation in an entertainment center using an old 250W power supply and 6 case fans. Right now there is a DVR, Xbox 360, and a stereo amp in an enclose space that needs better circulation b/c of the increase of temperature. A computer also sits in a space next to the other three and also needs circulation. The only reason that these are in a enclosed entertainment center is that the woman hates seeing cords around the TV. "I want it to look clean, not like your office." - the woman

I am going to cut four holes in the back of the space for the four fans, and then plug the fans into the stand-alone power supply. Right now the supply works but without a switch the fans will not run. All four fans have 4-pin molex connections.

I need to find out how to get the power supply to run the 4 fans so I can do the same for the computer enclosure.

if i understand what your asking, you are trying to jump your ATX PSU without a mobo. that can be easily accomplished by connecting the Green and Black wires on connector that goes to the mobo from the PSU.

Have a look at this worklog I did for making a test PSU. You could follow the same basic principles for what you want to do.

The link showed me exactly what I was looking for.

So I just need to get an on/off switch to connect the #14 & #15 wires.

In regards to the rest.. Black, Red and Yellow are all power? Green for 'ON'. Are the rest needed, or what are they used for??

I also have a 4-pin (2x2) connection that is by itself and also plugs into the motherboard. What is this??

Also, if i want to extend the wires to any length is there a special type and gauge of cabling that works best for this? Copper?

How's the best way to connect the switch? through the 20 pin or just chop extras at the PSU? Then should I just get a soldering iron, or could the twist caps and tape work? How does the heatshrink tubing work? never heard of it before.

I appreciate all the help. This forum works wonders if your clueless on a project.

Yellow is the 12 volt line
Red is the 5 volt line
The black wires are grounds

As for the 4 pin connector, you dont need it.

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I also have a 4-pin (2x2) connection that is by itself and also plugs into the motherboard. What is this??

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It gives extra power to the cpu.. usually. You could use it for 12V output, if you need it..

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Also, if i want to extend the wires to any length is there a special type and gauge of cabling that works best for this? Copper?

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You can use any type of wire, but you have to take into account what current passes through them. Therefore, I would stick with stock wires. You can buy the same type of wire from electrical shops. I'm not sure what thickness your wires are, but I think they are standard.. So, if you look for something similar in a shop, or wait for someone who knows the name/gauge of this type of wire.. you can find some wires here

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How's the best way to connect the switch? through the 20 pin or just chop extras at the PSU? Then should I just get a soldering iron, or could the twist caps and tape work? How does the heatshrink tubing work? never heard of it before.

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You could chop the connector, if it bothers you. Then solder the connections you need, cut the rest of the cables and make sure there are no shorts :) Twisting wires together works, but it doesn't look nice or tidy. Acceptable in the beginning, you will not like it after..

Heatshrink tubing is a special thing used to tighten things up, works also like an isolator and looks nice. It is made of a plastic that gets smaller / shrinks when heat is applied. You need a hair drier at least for this, if not a heat gun :)

As the others have said^
But first, DO NOT OPEN UP THE POWER SUPPLY!
I did with mine, but I do have some experience in dealing handling the components inside as not to shock myself. It can be a big zap with the voltages stored in the capacitors in the PSU. It is possible you could die, unlikely, but is possible.

Now that is out of the way here is a quick MS Paint work of some random image that was on Google.

Rough, I know...
Basically if you used your original wiring to run to those "bus bars" that are in the image. I've also heard of them being called "chocolate bars". They have srew fittings that you can just strip the wiring and then put in place. No need to solder. You could trim the wiring down to the length you need to fit in nicely.
That way you can just screw in new wires of the length you need going to each fan and to the power switch.

For the application you are doing here is the colour coding for the wiring:
RED: 5V
YELLOW: 12V
ORANGE: 3.3V (not needed)
BLACK: Ground
GREEN: Power switch
GREY: Not needed (motherboard specific)
PURPLE: Not needed (motherboard specific)
BLUE: Not needed (motherboard specific)

The fans need to be hookes up to a power source, either 12V (yellow) or 5V (red) and to a ground (black). 12V will give you maximum air movement, but may be too loud for your liking. If so you could hook the fans up to a 5V source and the fan speed will be a lot less, therefore a lot quieter, but will have less cooling. It might be enough for what you need though.

The green needs to go to one side of a switch, a black wire to the other.

The purple, blue, grey, orange and any left over red yellow and black you can just trim off short and place some heatshrink over the end to stop any chance of a short circuit.

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Originally Posted by dgrmkrp

Heatshrink tubing is a special thing used to tighten things up, works also like an isolator and looks nice. It is made of a plastic that gets smaller / shrinks when heat is applied. You need a hair drier at least for this, if not a heat gun :)

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A cigarette lighter will work to if you are careful. I find it's quite useful for jobs like that.
Basically heatshrink is a rubber tube that shrinks down to a smaller diameter and insulates the wiring from any shorts. I used it over solder joints. It's like having a replacement for the original plastic insulation on the wires. It comes in many colours and sizes for thin wire to stuff you could heatshrink your arm.
Cut cut a piece off and make sure it's longer than the part you are trying to cover, thean apply heat and watch how quick it shrinks!

I'm not sure where you are in the world, but in Australia both the heatshrink and bus bar are available at Dick Smith Electronics and Jaycar, I'd imagine Tandy or similar would have it in the US. If you are elsewhere in the world, find your local electronics parts store. Cost should be under $10.

Awesome,

Those ideas and links helped me define my ideas better. I have finished the converted PSU and currently working on the entertainment center modifications. My living room is a mess and there will be pictures to come. The entire system will be something really impressive that helps improve cooling.

Thanks guys. The system is working great.

I'm a bit late coming to this discussion, but I bet an old AT psu would work great for this, as it already has a switch attached. At least it's a use for them, since they would otherwise just end up as trash.

This has inspired me to mod my entertainment center too... some 120mm fans to improve airflow in and around my xbox(s), dvd player, and media PC, plus a couple of lights with a seperate switch to turn them off during movies. :D