Epson 3865X Plus - Manual (Page 206)

3. Locate one of the power supply cables that lead from the
power supply in the computer (behind the horizontal drive
bays). The cables are labeled P1, P2, or P3 and have a clear
plastic connector on one end. You can use any of the three
cables. As shown below, the end of the connector has two
notched comers.
power supply cable power supply socket
notched
corners
\
notched
corners
The power supply socket on the back of the hard disk drive
is next to the cable connector you just connected. The
power supply socket also has two notched comers, as shown
above.
Align the power supply cable connector with the power
supply socket so that the notched comers on the connector
line up with the notched corners of the socket.
notched corners
Installing and Removing Disk Drives B-15