Note the shape of the recess for the Mode/Switch Knob.
This Knob assembly is held in place with a screw in
the center plus a special black color plastic clip.
The next picture shows this clip. This clip is installed
from the underside of this cover at the little rectangle hole.
The other slot to the left of the recess is for the cable.
Hard to see in this photo, but the AEL button shows. This
is held in place with a screw. If you took it off like I
did put it back on.