Epson EQUITY 386/33 PLUS - Manual (Page 102)

3. Align the connector with the socket so that the row in the
connector with the blocked hole lines up with the row in
the socket with the missing pin, as shown below.
Make sure the holes fit over all the pins and then push in the
Connector.
4. Locate one of the power supply cables that lead from the
power supply (behind the horizontal drive bays). The
cables are labelled P1, P2, and P3; you can use any one.
5-14 installing and Removing Drives