Epson 3865X Plus - Manual (Page 229)

Make sure the cable connector fits properly onto the drive
interface and then push the connector onto the interface.
Caution
If you do not correctly align the connector, you could
severely damage your diskette drive when you push it in.
If you removed a hard disk drive from the vertical mounting
position, go to step 6. If you did not, go to step 8 for
instructions on connecting the power cable.
6. Locate the hard disk drive ribbon cable that you removed
from the drive in the vertical mounting position. Follow the
instructions below to connect the middle connector on this
cable to the vertically mounted drive.
As shown in the illustration below, there are two rows of
holes in the middle connector. One of the holes is blocked
with
a plastic plug.
‘blocked hole
B-38
Installing and Removing Disk Drives