The red and black cables seen here connect to the DC power socket. The blue connectors will not be present on other units as this was a temporary fix until the proper parts could be ordered.

Make a note of the wire orientation (red and black wires) and connector since all units may not be the same. The connector can only insert in one direction. Also, note that the connector on this unit does not seem to push fully into the housing.

Disconnect the cable and unscrew the nut on the DC socket. The nut is recessed in the base plate and needle-nose pliers may be the best tool to use but it may scratch the base plate finish.