I have been using this to test a multitude of different circuits and devices!
Step 1: Materials
A computer power supply.
Several eyelet wire connectors.
different coloured binding posts.
An LED(i used an old computer power led)
Power resistor. 10Ohm 10W should work.
Optional is a cigarette lighter adapter (CLA).
Step 2: Disassembly
Make sure it is not connected to mains
Make sure that it is fully discharged.
Remove the cover screws.
Remove any chassis connectors.
Remove the mainboard screws.
Remove the power supply circuitry from the metal chassis.
Cut all the output wires to about 6-8 inches from the mainboard.