Epson 4000 - Manual (Page 63)

Remove the two retaining screws securing the power supply
to the back of the computer and the third retaining screw
holding the power supply to the base of the computer, as
shown below. Be careful not to disconnect any of the cables.
Slide the power supply out of the way.
2. Remove the retaining screw securing the option slot cover
to the computer, as shown below. (Keep the screw to secure
the option card to the computer.)
4-16
Installing
and Removing Options