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Homemade PSU tester

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Aug 19, 2004
I don't know if anyone has done this, I have not found anything on it yet.

ATX Power supplies do not have a power switch that will turn the unit on. They do have a rocker switch in the back that will allow the unit to get power but it will not spin the fan(s) or activate the various 3.3, 5 and 12 volt lines. Turning the unit on and off is done though the motherboard, so the unit needs to be plugged in to work. One way to circumvent this situation is to take a conductor (I usually use a paper clip) and short out the power lead (green wire, pin 14) with the nearby ground (black wire, pin 15) on the 20 or 24 pin adapter.
The short has to remain in place for the duration of testing and sometimes keeping a paper clip from popping out is hard to do. So, I
decided to make my own foolproof power supply turner on-er

parts and tools
old motherboard (will be destroyed)
copper wire
soldering iron/solder
Rotary tool

Concept: Make a device that will short out pins 14,15 on a power supply

I have a few old motherboards laying around that don't work and I have not gotten around to throwing them out so I decided to cut one up for parts.
Using the rotary tool cut out the 20 or 24 pin power adapter. (The plastic adapter and the underlying PCB) Burnish the contacts connecting the pins that will ultimately accept the green and black wires at pins 14 and 15. In a 20 pin adapter it is the third and fourth pin from the empty pin in the same row. (refer to a power supply to get the right end to start from). Cut a small piece of copper wire just long enough to span the two contacts (~1/4"). Solder the wire to the two contacts. One more step. This will work for a 20 pin PSU but will not fit on a 24 pin unit so you need to cut off the plastic wall furthest from the soldered pair.
That's it. To test a PSU, slip this baby on the 20/24 pin wire bundle and turn on the power.

Or, you could just buy one of these for $20


Oct 5, 2001
Long Island
I have one of those. The only thing I wish it had was a load.. This just turns it on, and checks the voltages, which is fine. However, will only give you good data from a truly bad power supply..

I think your idea may be something to consider, as long as its not huge...
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Oct 11, 2005
Concept: Make a device that will short out pins 14,15 on a power supply

For at least 10 years I have been taking a staple out of a staple gun. Straightening it out and then folding it around a pair of needle nose pliers into a U shape.


A bit of left over wire works well too heck even a paper clip.

If you have a really small pair of needle nose pliers, you can jam them in there. A pair of fingernail scissors works well too.

Paper clips/staples work best IMHO though cause they will stay in place :) And you are pretty much guaranteed to have one or the other laying around wherever you go.
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