iFixit

Slightly lift the top edge of the display out of the outer case.

Do not lift it too much. There are several cables attaching the display to the logic board.

Pull the vertical sync cable connector out of its socket on the LED driver board near the top left corner of your iMac.

Rotate the display out of the outer case enough to disconnect the LED backlight power cable from the LED driver board.

Disconnect the LED backlight power cable by depressing the locking mechanism while pulling the connector away from its socket (toward the bottom edge of the iMac).

Grab the plastic pull tab secured to the display data cable lock and rotate it towards upwards.

Pull the display data cable straight out of its socket on the logic board.

Do not lift up on the display data cable, as its socket is very fragile. Pull the cable parallel to the face of the logic board.

Disconnect the LCD thermal sensor cable connector from its socket on the logic board.

Carefully pull the display toward the top edge of your iMac and lift it out of the outer case, minding any cables that may get caught.

Remove the following four screws:

• One 9.3 mm T10 Torx screw with a large head
• Three 9.3 mm T10 Torx screws with a normal sized head

Pull the optical drive thermal sensor connector toward the top edge of the iMac to disconnect it from its socket on the logic board.