Apple iMac G5, 20-inch - Manual (Page 59)

iMac G5 (20-inch) Take Apart - Logic Board
3. Using a T-8 screwdriver, remove the two fan duct screws and lift the duct off the logic
board. Note: These two screws are longer than the other silver screws securing the
logic board to the midplane chassis.
4. Remove the three hard drive screws. Next, lift the hard drive up a bit and disconnect
the hard drive data and the hard drive power cables on the left side. Lastly, disconnect
the thermal sensor and the inverter cable (located near the copper heatpad).