Epson 2000 - Manual (Page 81)

If you are installing a 3.5inch diskette drive with a header
connector, see page 4-13 for instructions on connecting the
cable.
3. Locate one of the power supply cables that lead from the
power supply. (They have multi-colored wires and a plastic
connector on the end.)
4. Align the notched corners of the power supply cable
connector with the notched corners of the drive’s power
supply connector (such as the one shown below). Make
sure the holes fit over all the pins and then push in the
connector.
notched
corners
4-20 Installing and Removing Drives