Remove four 4.6 mm flat head screws.

Remove one 4.3 mm flat head screws.

Lift off front lens board.

Note the position and number of shim washers at each screw location. They need to be installed in the same positions during reassembly.

If the top cover is still attached, lift the bottom of the lens board first. There is a lip around the top of the lens mount that engages with the top.