Epson EL 3S/33 - Manual (Page 74)

If you are installing a hard disk drive in the upper
horizontal bay, make sure you use the proper hard disk
drive ribbon cable and connect the drive to the hard disk
drive connector. Also, if this is the second hard disk drive in
your system, make sure you set the jumpers on both hard
disk drives to indicate which is the master and which is the
slave drive.
2. If the drive connector extending from the back of the drive
has gold contacts on both sides, use the card-edge
connector on the ribbon cable. Make sure you align the
key-way (the plastic divider) with the gap in the drive
connector.
If the drive connector contains a series of pins, use the
header connector. Identify pin 1 on the drive and align the
connector so that the red wire is at pin 1.
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.)
Installing and Removing Drives 4-15