Epson Equity 286 PLUS - Manual (Page 129)

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.
Both sockets have a notch on one side. Connect the
diskette drive cable first. As shown below, there is a tab on
one side of the connector.
ribbon cable connector
diskette drive socket
Installing and Removing Options 5-39