power+supply

toc =Power Supply=

Computer Power supply is cheap and reliable source of power. The power supply we are using has the following specs. The +12V rail can provide 120 W of power, and +5V rail can provide 150 W of power. These are more than enough for us. To use this power supply unit (PSU) we need to make some rudimentary changes.



Components Required

 * DC Toggle Switch
 * LED + Resistor - 10 ohms, 10 W
 * Power Resistor - 330 ohms
 * Binding Posts
 * Banana Plugs or Similar
 * Heat Shrink Tubing

Steps to Transform Power Supply

 * All the connecters were cut off leaving enough length for connections.
 * Wires are colour coded with values: Red = +5V, Black = GND, White = -5V, Yellow = +12V, Blue = -12V, Orange = +3.3V (not used), Purple = +5V Standby (not used), Gray = power is on (output), and Green = Turn DC on (input).




 * Bundled and soldered all the wires of the same colors together, leaving one red (+5V), 3 black (GND) wires for other use later.
 * To make space for binding posts, LED and ON/OFF switch holes were drilled until right space were achieved.




 * The +5V, GND, +12V, -5V, and -12V wires were soldered to binding posts.[[image:http://img97.imageshack.us/img97/2343/sdc15869resize.jpg width="475" height="420" align="center" caption="Same Coloured Wired Connected Together"]]
 * Connected one of the red wires to the power resistor, 10 ohms, 10 W, and one of the black wires to the other end of the power resistor to fool PSU that there is a load so that PSU turns ON.




 * One black wire was soldered to a resistor, 330 ohms, which is soldered to cathode of the LED. The other end of LED (anode) is connected to gray wire.
 * One remaining black and green wires was soldered to the DC toggle switch acting as ON/OFF switch.
 * All the connected were insulated using heat shrink tubing.
 * LED, ON/OFF switch and binding posts were secured.