Epson 3865X Plus - Manual (Page 140)

Replacing the Cover
After you install (or remove) optional equipment or change
jumper settings, follow these steps to replace the computer’s
cover:
1. Turn the computer around so you are facing the back panel.
2. Hold the cover so that the side with three tabs on the edge
faces away from you. Then position the cover above the
computer at an angle, as shown below.
5-34 Installing and Removing Options