Epson EL 486UC User Manual page 78

Locate the hard disk drive connector on the system board.
2.
Position one of the end connectors so that the red wire
3.
aligns with pin 1 of the connector on the system board.
There a "1" printed on the system board to identify pin 1.
is
Make sure the holes in the cable connector fit over the pins
4.
in the system board connector; then push in the cable
connector.
Caution
If you do not correctly align the holes with the pins, you
could severely damage your system board when you push in
the cable connector.
Installing and Removing Drives
4-5