How to replace the power supply of Apple iMac 20 inch

Apple iMac power supply replacement – How to replace the power supply of Apple iMac 20 inch – How to remove the back cover – How to remove the power connections  - How to remove the power supply

Tools Required
Use the screwdriver provided, or a Phillips #1 screwdriver, preferably with a magnetized tip
Flat blade screwdriver
Screw tray or equivalent to hold the screws

Power supply Location

Important Things Remember 

1. A spares kit is included with the replacement part. The kit includes:
# a Phillips #1 screwdriver
# extra screws
2. All customer removable screws are brass colored. Do not remove screws unless they are brass colored, or you will void your warranty.
3. Ground yourself when working on the computer. The procedure will show you how to ground yourself.
4. Do not pull on individual wires when disconnecting a part; pull on the connector.

Opening the Computer
1. Turn off your computer by choosing Shut Down from the Apple menu.
2. Disconnect all cables, and unplug the power cord from your computer.

3. Place a soft, clean towel or cloth on the desk or surface. Hold the sides of the computer and slowly lay the computer face down as shown.

4. Locate the three case screws circled below. You may have to lift the metal foot to locate the middle case screw. 

Note: These screws are captive; they are part of the display/bezel assembly and cannot be removed.
5. Using the tool provided, or a Phillips #1 screwdriver, loosen the three captive screws.
Note: Turn the screws counterclockwise until they stop turning.

6. Holding the back cover by the metal foot, tilt the cover up and lift it off the computer. Set the back cover aside.

Removing the Power Supply

1. Ground yourself. Touch the metal surface (as shown below) on the inside of the computer to discharge any static electricity.
Warning: Always discharge static electricity before you touch any parts or install any components inside the computer. To avoid generating static electricity, do not walk around the room until you have finished installing the part and closed the computer.

2. Locate the power supply  from location picture .

3. Remove the screw on the right and loosen the other two screws by turning them counterclockwise five to eight revolutions. 

Note: The middle screw and the screw on the left are captive; they will not come out of the power supply.

4. Disconnect the power supply cable by pressing the connector release tab and using a wide, flat blade screwdriver to pry apart the connector.

5. Pull on the connector, not on the cables.

6. To unlatch the power supply, tighten the middle case screw by turning it clockwise five to eight revolutions.

7. Lift up the power supply at the sides approximately five mm or until it touches the middle case screw.

8. Tilt up the power supply until it clears the edge of the main circuit board. Lift it out of the computer and set it aside.

For installing the new or repaired power supply go in reverse order