Epson EQUITY 386/33 PLUS - Manual (Page 57)

Both the diskette drive and hard disk drive sockets are
located on the main system board on the left side of the
subassembly, as shown below.
diskette drive
Both sockets have a notch on one side. As shown below, there is
a tab on one side of the connector. Connect the diskette
drive cable first.
tab notch
Accessing Internal Components 3-15