Epson Equity 320SX PLUS - Manual (Page 140)

Follow these steps to install the hard disk drive in the vertical
mounting position:
1. Place the hard disk drive on the right side of the
subassembly with the mounting plate facing up and the
ribbon cable and power supply sockets facing the back of
the subassembly.
mounting plate
2. Locate the hard disk drive ribbon cable that came with
your computer. It is a flat cable with three connectors,
one on each end and one in the middle. (If you are
installing a second hard disk drive, the cable may be
attached to the other drive.)
7-12 Installing and Removing Disk Drives