Sony CLM-V55 Operating Instructions Manual page 25

Top panel
Fit the projection of the top panel into the groove along the top of the frame.
Note
¦ ˎ
The side panels only open if the projecting end of the spring is placed
ˎ ˎ
correctly into the groove. If the panels do not open, reattach the spring
so that its projecting end is in the groove.
25-GB