Non-permanent Rigging of a Computer PSU for RepRap (with pictures!)

===How to rig up a computer power supply for use with RepRap without ruining the PSU's potential as a computer PSU===

Overview:
Both of the ways listed at [reprap.org] for converting a PC PSU to a RepRap power supply require (in my eyes) ruining of the PSU for what it was originally intended for: supplying power to a computer. Thus, with some handiwork with paperclips and some other material, I went about fashioning the required hardware, leading from the connectors themselves, rather than splicing preexisting wires. Here's what I came up with.

NOTE: I do not yet have a RepRap to test this, but the power supply did boot up (which is obviously a good sign ).

Required Materials:
ATX PSU (obviously)
Paperclips
Duct tape or electrical tape
Wire cutter
Pliers
Wire
Soldering iron
Solder flux
Solder
Wire stripper
Scissors


1] Fashion two make-shift jumpers from paperclips, like in the image below. These will be used to connect the green (power on) wire to a ground (black) wire, and the 3.3V sense wire (brown or orange) to a 3.3V+ wire (orange). Make sure that when you test fit them into the connector that they're not too loose or too tight.


2] Insert the jumpers based on the diagrams below (connecting pins 1 to 11 and 13 to 14).



3] Cover the 20 pin connector up with duct tape to prevent the makeshift jumpers from becoming dislodged.


4] Now we will make a set of wires that can easily insert into one of the remaining connectors (I used the 4 pin CPU connector because the molex were too loose to work with my paperclips). Cut two lengths of paperclips and bend them into a zig-zag shape. This zig-zag will help separate them so they are less likely to short circuit. See picture under step 5 for a visual of the paperclips and their relative lengths/shapes.

5] Solder the pieces you shaped in step 4 to two separate lengths of wire (I used two 18" copper wires).


6] Shrink tube the soldered areas.

7] Insert the paperclip ends of the two wires into a 12V+ (yellow) connector and a ground connector.


8] Slide duct tape into a valley of the PSU connector to create a barrier between the two wires, decreasing chances of an accidental short-circuit. Wrap it around one of the sides of the connector and wire.


8] Finish insulating the paperclips with duct tape. Here's what mine looked like after this step:


9] You're done! Now you have a PSU that doesn't require a motherboard "power-on" command to start up (just hit the on switch in the back to turn it on) with a 12V+ and ground wire to connect to your RepRap!


Edited 1 time(s). Last edit at 11/18/2010 10:17PM by An Original Name.

When I built my liquid cooled PC I used a connector like this to supply power to the components while not powering the motherboard. Very useful for testing the pump and system for leaks. I have not looked into the pinout requirements for a reprap but looks like this might work as well?

Bypass Adapter

I simply opened my PSU, wired up a switch between the green wire and ground (spliced in so the green wire still goes to the 20 pin connector), and mounted the switch on the side of my RepStrap. That way I just flip that switch and the PSU turns on and I can just leave the main PSU switch on. Gives me a convenient kill switch without having to reach for the PSU. No need to tape a paper clip in the 20 pin connector too, although I'm sure that works just as well .

Edit: Oh, and it's still 100% compatible with a computer this way.

Edited 1 time(s). Last edit at 11/18/2010 11:50PM by NewPerfection.

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I would've picked up an opposite gender connector that connects to the cable, then modified that

hintss Wrote:
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> I would've picked up an opposite gender connector
> that connects to the cable, then modified that


That would be the "non-ghetto" version.

Very nice guide! But needs more duck tape :p
Oh, and hint hint.

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-Nudel
Blog with RepRap Comic