Step 22
Use a firm plastic edge to scrape the thermal material off the heat sink.
Step 23
Apply a new layer of thermal paste to the copper heat conduit.
When replacing the logic board, make sure all cables are routed around and above - not under - it, and to connect the two cables that do go beneath before pushing the board into place.
Place the logic board back in the computer, trying not to move it around once the processor has come into contact with the newly-applied thermal paste.
Step 24 — Speakers
On computers with an ambient light sensor, you will remove an ambient light sensor board instead of a placeholder yellow plastic board.
Remove the two black Phillips screws from the yellow plastic board above the USB port on the left side of the computer.