Step 19
Lift the optical drive out of the computer from the side with the connector on it (mind the small metal bracket that pops out with the drive, keep this with the optical drive).
Don't forget the bracket when reassembling the computer.
Step 20 — Logic Board
If you have already removed the display or hard drive, you may have already removed some of the cables described in this step. You may also ignore their presence in the following images; they do not further affect the disassembly procedure.
Disconnect the indicated 13 cables from the logic board, starting in one place and moving around the board.
Step 21
There should be no cables connected to the top of the logic board at this point.
Remove the following 12 Phillips screws from the logic board:
Six 4 mm around the edges of the logic board.
Two 5 mm securing the right speaker to the logic board (move the speaker off of the logic board).
Three 6 mm with wavy washers in the upper, left corner of the logic board.
One 4 mm underneath a black bumper in the back right corner of the logic board.
One 4 mm screw may not be present on some logic boards.