Flip the system over

Remove the four outer screws (you may want a small cup to keep your screws in.)

Take plastic top off.

Remove the nine inner screws.

Remove metal piece.

You now have access to your circuit board. (If you wish to remove the circuit board, continue.)

Remove the two screws highlighted in picture to remove the circuit board.

Lift the black piece of plactic up.

Lift up the metal piece.

You now have access to the inside of the bottom plastic piece.

This is the circuit board.

Do the steps backwards to reassemble.