Epson 20 - Manual (Page 129)

Replacing the hard disk drive controller card
1. Reinstall the hard disk drive controller card in the appropriate
slot and secure it to the back of the computer with the retaining
screw.
2. Reconnect the drive light wire to the card.
Removing an Option Card
If you later need to remove an option card, simply reverse the steps
you followed to install it. Remove the screw securing the card to the
back of the computer and pull the card straight up and out of the
slot. Then carefully wrap the card, preferably with the original
packing materials, and place it inside its box for safe storage. Cover
the end of the empty option slot with the original metal cover and
secure it with the retaining screw.
Installing Options 6-17