My Dad has made a really neat and simple breakout for an ATX supply to be used as a bench supply. Lots of folks use ATX supplies as bench supplies, but usually stick the binding posts for power on the supply itself. That's a great way of doing it (we do that too ), but if the supply goes bad, or you just want to check the voltages, it's a bit of work. I've pasted his assembly instructions and pictures below:
ATX Supply Breakout
An ATX power supply can make a good cheap bench top power supply, and this breakout and is also good for testing ATX power supplies. This breakout provides +3.3, +5, +12, and -5 volts.
Most of the parts were salvaged from old equipment.
Parts required: 5 binding post, differant colors are best
1 single pole power switch
1 green LED
1 470 to 510 ohm resistor
1 ATX power connector ( removed from a deed motherboard )
1 plastic project box 4.5 X 2.5 X 1.25 inches
To test an old ATX power supply to see if it works and the voltages are correct, put a jumper between the green wire on the power connector and any black wire (there is a black common beside the green wire).
Now if you have an old ATX power supply you know does not work it is good for useing the wiring harness for the correct wire colors, makes it easier for wiring the male connector.
Assembly is quite easy, drill out the plastic box for the five (5) binding posts, the power switch and LED. Drill a hole in one end of the box for the wires to pass through but not to big.
Wiring colors needed are Red, White, Yellow, Green, Orange and Black. I used two (2) Black wires for the common so as to carry the current.
The male connector wiring is as follows:
Pins 3 and 7 are Black for the common
Pin 10 is Yellow for the +12 volts
Pin 11 is Orange for the +3.3 volts
Pin 14 is green for the power on switch
Pin 18 is white for the -5 volts
Pin 19 is Red for the +5 volts
I used the Red post for +3.3 volts, Blue for the +5 volts, Green for the -5 volts and a smaller red for the +12 volts and Black for the common.
TIP: If you place the male ATX connector on the power supply connector it makes it easier to keep the color code together while soldering the wires onto the connector. Place heat shrink tubbing over the wire ends after they are soldered to the connector.
For the power switch, the Green wire will go to one side of the switch and the other side of the switch will go to the common ( the black wire ). (Note: the power on the green wire goes to ground or common to turn the power supply on).
Solder the resistor to the positive side of the LED, and put a bit of heat shrink tubbing over the resistor to protect the wires. Solder the other end of the resistor to the +12 volt binding post ( yellow wire ) and the negative side of the LED to the black binding post ( black wire ).
Once all of the wiring is completed check it before you close up the box.
Testing is easy, connect the ATX connector together, make sure your power switch is off, plug your power supply into a 120 volt outlet, ( some ATX power supplies have a power switch just above the main power connector, make sure it is in the ON position ). Connect your bench meter to common and any one of the binding post voltages and turn on your power switch.
If all went well test each voltage and you have good bench power supply.
If the ATX power supply should fail in the future just plug a new one in.
(Remember to be extremely careful when dealing with power supplies and outlet voltages -- use these instructions at your own risk!).
And here are the accompanying pictures that he's sent: