NEC POWERMATE PRO2180 Manual page 108

Unscrew the three thumb screws at the rear of the
3.
system unit. If you installed a padlock on the back of the
system, unlock the padlock and remove it.
From the rear of the system, grasp the handle and pull it
4.
back so that the cover clears the padlock slot.
Removing cover screws
Installing Options 5-5