How to Replace the Power Supply on Your PC - dummies

How to Replace the Power Supply on Your PC

By Dan Gookin

If the power supply is dead, it needs to be replaced. You can pay to have this done or simply note the power supply’s product number and search for a replacement unit locally or on the Internet. The key is knowing the part number. For that, you have to remove the power supply:

  1. Open the computer’s case.

  2. Lay the computer on its side.

    The open end of the console should be facing up. You don’t want to work on the power supply when the console is in a vertical position because it’s more difficult to remove it that way.

  3. Detach all the power cables from all the devices in the console.

    Disconnect power cables from the disk drives and the motherboard, plus any other devices they’re attached to.

  4. Remove the power supply screws.

    The screws can be accessed from the back of the console case. Be sure that you’re removing the screws that anchor the power supply, not anything else.

    Some power supplies use four screws; some use three.

  5. Confirm that nothing is in the power supply’s way.

    Some smaller consoles may have things that need to be removed before the power supply can be freed. You may have to pull out a DVD drive to get a power supply out. Or remove the entire console case to remove the power supply from the top rather than from the side.

  6. Liberate the power supply!

    When you cannot remove the power supply, you forgot one or more screws.

After the power supply is free, you can search it for its part number or ID. You can search the Internet by using the part number along with the key words power supply. Or, you can visit the manufacturer’s web-site to order a spare if that’s an option. Most power supplies are fairly standard.

Consider getting a replacement power supply that packs more wattage or perhaps has extra cooling power. But remember that the replacement must still fit into (or be compatible with) your PC’s console. If possible, take the old power supply with you to the parts store to ensure that its dimensions — especially the cable lengths — are identical.

To install the replacement, follow these steps:

  1. Unpack the new power supply.

    If it came with specific instructions, follow them.

  2. Ensure that the PC case is open and ready to receive the new power supply.

    If you had to remove anything to get the power supply out, you need to remove those same things to put the new power supply in (unless you just left your PC hanging open in the interim).

  3. Anchor the power supply by screwing it back into the case.

  4. Reattach all the power cables from all the devices in the console.

    Every disk drive needs power. The motherboard needs power. Anything else?

  5. Set the computer upright again.

  6. Close the computer’s case.

    Remember not to tighten the screws until you know that the computer powers up.

Watch Video 184 for a demonstration of removing and then reinstalling a PC’s power supply.