The power supply in your computer manages all of the power required to run each component of your computer. When this critical component begins to fail, your computer may power off unexpectedly, experience startup warnings or overheat. Several simple checks with a digital multimeter can uncover some of the warning signs of impending hardware failure.
1. Unplug your computer and disconnect all of the cables connected to your computer. If your unit is equipped with a power switch, turn the power supply off.
2. Place your computer on the anti-static mat. This step will prevent your computer from being damaged by static electricity.
3. Remove the screws that hold the sides of your computer in place and remove the outer casing.
4. Unplug all of the power connectors from all of the internal devices. Don't worry about unplugging any of the data cables because they are not connected to the power supply.
5. Check the sticker on the power supply and locate the voltage information. The voltage will be different depending on the wattage of your power supply. record the listed voltage of the power supply.
6. Plug the electrical cord into the power supply while it remains on the antistatic mat. If your power supply has an on/off switch, turn the power supply on.
7. Switch your multimeter to the range that is appropriate for reading the voltage from your power supply. If your power supply's voltage is 125 volts, switch your multimeter to read a range of 100-200 volts. Some multimeters may not offer a range, so you may need to choose the approximate voltage on a dial.
8. Locate the largest group of wires coming out of the power supply. This bundle is the group of wires that delivers power to the motherboard and not individual peripherals.
9. Connect the multimeter's negative (black) probe to the ground wired pin. Ground wired pins are easily identified because they are always black. Connect the positive (red) probe to the power line. The power line is recognizable because it is always the green line.
10. Record the voltage that appears on your multimeter. If your power supply sticker shows a voltage of 135 volts, you should be seeing the same reading on the multimeter. If you see a much lower or higher reading, your power supply has malfunctioned and it will need to be replaced.
11. Turn off the power supply after you have finished testing the ground wired pin and the power line. Reconnect all of the power connectors, replace the sides and restart the computer.
- Anti-static mat
- If your power supply does not appear to have any problems after testing it with the multimeter, check all of the power connectors to make sure they are properly plugged into the devices.
- Opening your computer may void your warranty. If your computer was put together by someone else, check the warranty before opening your computer.
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