Epson ActionTower 3000 Computer User Manual page 76

5. Position the ribbon cable's system board connector so that the
side of the ribbon cable with the red wire is closest to the
pin identification markings "1" and "2" printed on the
system board.
6. Make sure the holes in the ribbon cable connector fit over the
pins in the system board connector; then push in the ribbon
cable connector.
If you do not correctly align the holes with the pins, you
could severely damage your system board when you
push in the ribbon cable connector
7. Now locate the side of the hard drive connector that contains
pin 1. The number "1" or "2" may be stamped on the
connector casing or printed on the drive's circuit board to
identify the side of the cornnector containing pin 1. If the
number does not appear on the connector casing, remove
the drive and turn it over to check the circuit board.
4-6 lnstalling and Removing Drives