Epson EPI-4000 User Manual page 128

7. The option board cover is part of the paper tray. Lift up the
option board cover and slide it out from underneath the paper
guides, as shown below. Then remove the option board cover
from the printer.
8. To make room for you to insert the memory board, move the
paper guides to the left as far as they go. Then hold the memory
board as shown below and insert its connector into the
connector on the right side of the printer's main control board.
Using a Memory Board
Options
4-13