How to Troubleshoot a Computer Power Supply

The power supply is the computer's central nervous system. It converts electricity from the wall outlet into power a computer needs to run all of its components. If it is not working, the rest of the computer's components will stop working, too. Symptoms include not starting up at all, rebooting unexpectedly, not all components such as CD drives starting up, and components not functioning correctly. Remember that you are dealing with an electrical device and should use caution while troubleshooting.

Things You'll Need

• Screwdriver Working computer power cable Wall outlet on a different circuit Working power supply

Instructions

1. Exchange the existing power cable with a known working cable to check if you might need a new one. If the computer still does not turn on with the working cable, reinstall the original cable.

2. Move the computer to another wall outlet that is on a different circuit. If it still does not turn on, move it back to its original location.

3. Check the power supply for any burning odor that might indicate it has burned out.

4. Unplug the power from the back of the computer and use a screwdriver to take the side panel off the computer. Make sure that the power supply is connected to the computer's motherboard.

5. 

   Note anything that is not ordinary, such as a popped or oozing capacitor on the computer's motherboard.

6. Check to see if other components appear burned out or broken. If everything looks all right, switch out the power supply with a working one and test it by turning your computer on.

Tips & Warnings

• Always test another electronic device on the same outlet to make sure it's working. Make sure there aren't too many devices plugged into the same circuit, like multiple printers and computers plugged into a single power strip. Use a power supply that will sufficiently power your system. Under-powering the system can harm other components in the computer. If there is power going to the computer but it seems that certain components, like a CD or DVD drive, are not working, a working power supply should be substituted to ensure there is nothing wrong with those components.

• Do NOT open the power supply. It houses capacitors that store electricity even when the computer is unplugged, which can injure you. If you do not feel safe testing the power supply, take it to a professional who can test the components with the proper equipment. Some power supplies have a switch in the back labeled 110V/220V. If you live in the U.S., make sure the switch is at 110V. If you have it at 220 volts, you can damage the power supply further. If the power supply smells like it's burning, stop using and testing it with other working components. Immediately replace the power supply, and then continue with testing. If the power supply sparks or has any other volatile response while testing, immediately remove power from the computer and unhook the power cable from the wall. Bring it to a professional who can help safely replace the power supply.

Resources

• IT Professional site for further information.