How to Replace Your Computer Power Supply Unit

The other day, the power supply unit in one of my computers went out. So I went to a computer store, bought one and installed it. Then I thought, an article on how to do this might be a good idea. I built my computer from the ground up, and I had no formal training at all. So surely I can write about some simple repairs that anyone can do. This article is basically for PCs.

The power supply unit is located inside the back of your computer where your power cord is plugged in. On the inside of your computer, it will be the square metal box with a bunch of wires coming from it. You must get the unit that fits your case, either an ATX or an AT. Most cases now are ATXs there may still be some AT cases around though. First of all make sure your computer is turned off and unplugged from the electric socket. Then unplug all the cords from the computer. Don't worry about forgetting how to put them back, most cords will only fit in their own slot and others either are color-coded or have an image for where they go.

Now, you will have to open the case, this will be different for different cases, but should be easy to figure out. Once you have the case open, you must also unplug all of the devices that are in the case from the unit. Follow the cords coming from the power supply unit to the devices. You don't want to disconnect something from the motherboard or something else that you thought was connected to the power supply unit. Devices like CD drive, DVD drives, floppy drive and hard drives will have to be disconnected. Then unplug the power unit from the motherboard. This will be a large plug on the unit with lots of different colored wires connected to it. You can follow the wires to where it's connected to the motherboard.

Now remove the old unit by removing the screws from it in the back of the case. There will be four of them. Align the new power supply unit in the case so that the mounting holes align properly. Now screw the unit in place. You must plug the unit back into the motherboard. Now plug all the devices into the new unit, close the case and plug in all the cords including the power cord and you're ready to go. The voltage switch on the unit should come preset but incase it doesn't or it's been accidentally changed, make sure it's set for your country. North America and Japan use 110/115v, and in Europe they use 220/230v. The voltage switch is in a small rectangular slot somewhere on the upper part of the back of the computer.