During reassembly, when sliding the rear shell back onto the chassis, be very careful of the following areas:

The clips on the right side can easily dislodge the gears.

The top clip can scrape the surface‑mounted components on the top board.

Slide the rear shell over the chassis, making sure the rails on the bottom go into their cutouts on the shell.

Firmly squeeze the chassis and rear shell together until they "click" into place—you should feel and hear them snap together.

To make sure the shell is fully attached, make sure the rear shell screw holes are flush in the chassis.