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 optical drive near the connector to separate it from the logic board.
Lift the free end of the optical drive just enough to clear the fan cover. Lifting the free end of the optical drive too far may break the plastic positioning pins off the front bezel.
Lift the free end of the optical drive slightly, then pull it away from the edge of the rear case to clear the two plastic positioning pins.
Lift the optical drive out of your iMac.
When reinstalling your optical drive it may be necessary to set the bezel attached to the open end of the drive on the plastic positioning pins molded into the front bezel of the iMac and pull the connector side of the drive toward the edge of the rear case, bending it outward slightly, to properly seat the connector.
Remove the single Phillips screw securing the inverter to the logic board.
Lift the inverter straight up off the pins on the logic board.
Be sure to lift the inverter straight up off the logic board, as the connector pins are very long and easily bent. If the pins bend during removal, use the connector on the inverter as a guide to bend them straight.
Disconnect the inverter cable from the logic board by pulling it straight up from its socket.
Replacement note: it may be helpful to carefully reattach this connector before seating the midplane assembly, making sure the connector safely passes through the hole in the midplane assembly.
