ATX to Bench PSU Adapter

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EverestX's picture
SX Crew
Joined: 2009/05/15

Atx to Bench Breakout

This is a quick tut and expansion based on various Bench PSU mod's I have seen in the past, I've used them all for inspiration and have a few links below. This mod will provide you some of the most common voltages in any electronic (3.3v & 5v) or automobile (12v).


What's a bench PSU and what does it do?

Per wiki (
"D.C. variable bench supply (a bench power supply usually refers to a power supply capable of supplying a variety of output voltages useful for bench testing electronic circuits, possibly with continuous variation of the output voltage, or just some preset voltages; a laboratory (lab) power supply normally implies an accurate bench power supply, while a balanced or tracking power supply refers to twin supplies for use when a circuit requires both positive and negative supply rails)"

If you don't understand the use of multiple voltages at a reasonable amount of amps at your finger tips, move on to the next post.

Usable Voltages

+3.3, 2 x +5 (Standby and Active), +12 (check the web for 7v, 24v, combinations)
GND, -5, -12

Warnings Safety etc.

There is enough juice in a pc power supply to KILL YOU!

A typical bench psu is limited to 5 amps in most cases. Your average 300w pc power supply will provide around 20+ on certain rails. You'll have enough amps to melt your whole project should you not know what your doing. You've been warned.

Pc power supply's require a MANDATORY load. If a load is not present, you *WILL* Damage the unit. Creating a falso load on the unit creates heat. Heat melts things.

Fuses are good. I highly recommend them.


1 Pc power supply
1 Project box
6+ Terminals/Banana connectors (Really whatever you want to use for a post)
x Resistors (10w 10 ohm's or several 1w 10 ohms) *Do the research on your resistor sizes and choice*
20 or 24 pin female molex
1 switch
1 led

My additions
1 Female 4 pin molex
1 female usb port
1 xbox (v 1.0) heat sink with fan (to dissipate resistor heat)
In line/ external fuse holders (You can use as many as you like. Some opt for one per rail, others only put one on the ground, It's all in what you want)

This was jacked from


Here's some shots of mine - still need to add the Fuse Holders and finish USB connector hole - cell phone pics

atx2bench 1

atx2bench 2

atx2bench 3