Lay the iMac display-side down on a flat surface.

Loosen the three Phillips screws securing the rear panel to the iMac.

These screws are captive in the iMac. The center screw will stop turning after about 3.5 turns and the outer screws will stop turning after about 5.5 turns. Do not try to remove these screws from your iMac.

Lift the rear panel slightly near the bottom of the iMac.

Pull the rear panel toward yourself and remove it from the iMac.

Remove the three Phillips screws securing the power supply to the chassis.

The two leftmost screws are captive in the power supply.

To aid in removal, it may be helpful to lift the center screw slightly away from the midplane.

Rotate the center Phillips screw on the bottom of the iMac clockwise until the rear panel clamp contacts the edge of the case.

While depressing the connector lock, use a heavy duty spudger to pry the power supply connector away from its socket on the logic board.

It will be necessary to work from alternate sides until the connector is free.

Your power supply may have an ambient light sensor cable attached from the power supply to the logic board. If so, carefully use a spudger to push out the cable towards you using the sides of the cable alternatively to help you slide it out.

Lift the power supply slightly from its left edge, then grab each side and rotate the power supply toward yourself.

The power supply requires a large amount of force to remove. You may need to bend the edge of the front case toward yourself for enough clearance to remove the power supply.

There are several capacitors mounted to the logic board in close proximity to the power supply. Try not to disturb them, as they are delicate and may break off the board.

Rotate each of the two RAM retaining arms away from the RAM chip.

Pull the RAM chip straight away from its socket.

Repeat this process for the other RAM chip.

Be sure the RAM arms are rotated fully outward before installing new RAM chips.

Remove the following two screws:

• One 11 mm T10 Torx.
• One 10.6 mm T8 Torx.