An L-shaped bracket catches the lid when opened to prevent it from falling down. Opening it up, as if for a tall object, will unlock it. The top lid attaches with snaps rather than screws. When pressed in, the bottom end expands to block movement through the hole. When pulled out, the bottom contracts and the lid can be lifted off.
Front edge overlaps a plastic rail and prevents the front from lifting.
A double photo sensor mounted inside and tabs on the slide determine how far the slide has gone to tell it when to return. Top Cover With the top slide and covers off the top cover can be removed with just a few screws. Wire in the area is also wrapped with a glass braid to protect it from the heat as well. Probably to allow for small adjustments in position for universal usage and temperature changes. Copying light tube is wrapped in a modified parabolic reflector so that the light is directed to a mirror which reflects it toward the original which reflects the light back down and through a fiber optic sandwich onto the drum.