Fujitsu SPARC M10-4 Service Manual page 447

Stop the entire system.
Turn off the circuit breaker switches (CB switches) of the dedicated power
distribution unit (PDU) mounted on the rack for expanded connection.
28.4 Removing the Cable Kit
Caution -
28.4.1 Removing the cables for the connection between
the crossbar backplane unit and terminal board
Remove the front cover.
Remove all the fan units.
Loosen the two screws (A in the figure) securing the upper cover and then
slide the right and left stoppers (B in the figure) inwards. Then, remove the
upper cover (C in the figure).
Chapter 28 Maintaining the Cable Kit of the Crossbar Box 423