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Replacing the Power Supply in HP and Compaq Desktop PCs

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This document pertains only to HP desktop computers with the following computer case:
Image of the computer

Before you begin

  • You need a flathead screwdriver.
  • Remove the Pocket Media Drive, if it is present.
  • Turn off the computer, and then disconnect all cables. Disconnect the Ethernet or modem cable before disconnecting the power cord.
  • Transfer the computer to a clear, flat, stable work surface over a non-carpeted floor.
  • HP strongly recommends the use of an anti-static wrist strap and a conductive foam pad when working on the computer.
  • Do not remove a component from its protective packaging until you are ready to install it.
  • Because you must install the replacement power supply in the same orientation as the original part, write down the orientation of the power supply onto a piece of paper; high-connector or low-connector.
    Figure 1: The high-connector power supply has the power connector near the top of the computer
    Image of an upright power supply
    Figure 2: The low-connector power supply has the power connector near the add-in cards
    Image of an upside-down power supply
WARNING:The edges of metal panels can cut skin. Be careful not to slide skin along any interior metal edge of the computer.
CAUTION:This product contains components that can be damaged by electrostatic discharge (ESD). To reduce the chance of ESD damage, work over a noncarpeted floor, use a static dissipative work surface (such as a conductive foam pad), and wear an ESD wrist strap connected to a grounded surface.

Video overview

View the following video before using the steps in this article.
NOTE:For best quality on dial-up connections, wait until the video has fully loaded before viewing.

Replacing the Power Supply

Use the steps in this section to replace a power supply.
WARNING:Make sure the computer is disconnected from power before starting. Do not attempt to disassemble or repair the power supply, or this could cause personal injury and equipment damage. Always replace the entire power supply.
Step 1

Remove the right side panel.

For more information about removing the side panel, refer to the HP support document Opening the PC Case .
Image of removing the side panel
Step 2

Lay the computer on the side.
Image of laying the computer down
Step 3

Place the bottom of the computer toward you and locate the power supply inside the computer.
Image of the power supply inside the computer
Step 4

Trace the power supply cables to the system components:

  • Optical disc drives (1)
  • Hard disk drives (2)
  • Motherboard main power (3)
  • Motherboard fan (4)


NOTE:Recording the plug location, type, and orientation of each power supply connection helps ensure you correctly install the replacement power supply and connect it to all the system components. Any missed connection could prevent the computer or a component from working.
Image of the power supply cables locations for the system components
Step 5

Know how the cable connectors connect.

Plugs on the power supply are keyed and can be inserted only when aligned properly with the component connector. In addition, some power connectors have a latch that must be pressed or squeezed to release the cable connector from the socket.
Figure 3: Power connector (without a latch)
Image of a power plug without a latch

Figure 4: Power connector with a latch
Image of pressing the release latch on a power plug

Figure 5: Motherboard main power (with latch)
Image of the latch on a motherboard main power connector

Figure 6: Motherboard fan power (with latch)
Image of the latch on a motherboard fan power connector
Step 6

Press each plug release latch, if it is present, and disconnect the power supply cables for the system components:

NOTE:Your computer may not use all the plugs on the power supply. Record the plugs as you remove them from the system components.
  • Remove the power supply plug from each optical drive.
Image of removing the optical drive power supply
  • Remove the power supply plug from each hard disk drive.
Image of removing the system drive power supply
  • Remove the power supply plug from the motherboard main power connector.
Image of the main power connector on the motherboard
  • Remove the power supply plug from the motherboard fan power connector.
Image of the fan power connector on the motherboard
Step 7

Remove the four screws that secure the power supply to the back of the computer.
Image of the screws on a high-connector power supply
Step 8

Locate the power supply latch at the base of the power supply inside the computer.
Image of the power supply latch at the base of the supply
Step 9

Press the power supply latch (1), and then slide the power supply (2) to the left to release it.
Image of pressing the latch and sliding the power supply into the computer
Step 10

Move the power supply to the left and then down, freeing it from the computer.
Image of moving the power supply
Step 11

Lift the power supply out of the computer.
Step 12

Lower the replacement power supply into the computer. (The illustration shows a high-connector power supply installation.)

NOTE:You must install the replacement power supply in the same orientation as the original unit; make sure the orientation of your power supply before inserting it into the computer. Refer to the orientation that was written down earlier if necessary; either high-connector or low-connector type.
Image of inserting a high-connector power supply into the computer
Step 13

Align the power supply in the opening in the back of the computer.
Image of the power supply aligned in the opening in the back of the computer
Step 14

Slide the power supply to the right (toward the back of the computer) until the latch locks it into place.
Image of sliding the power supply into the opening in the back of the computer
Step 15

Insert and tighten the four screws that secure the power supply to the back of the computer.
Image of the screws on a high-connector power supply
Step 16

Route the power supply cables to each of the system components, and then connect them:

  • Optical disc drives (1)
  • Hard disk drives (2)
  • Motherboard main power (3)
  • Motherboard fan (4)


NOTE:Your computer may not use all the connectors on the power supply. Be sure to check your record and connect a power supply plug to each system component.
Figure 7: Unconnected power supply cables
Image of the unconnected power supply plugs
This image shows the power supply cables connected to each of the system components.
Figure 8: Connected power supply cables
Image of the power supply cables connected to the system components
Step 17

Set the computer upright.
Image of setting the computer upright
Step 18

Replace the right side panel.

For more information, refer to the HP support document Opening the PC Case .
Image of sliding the side panel toward the front of the computer

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