Sun Microsystems 220R - Manual (Page 149)

Caution - Be sure that the AC power cord(s) has been disconnected from the system
before continuing. Attempting to remove the power distribution board while the AC
power cord is plugged into a power source can result in serious personal injury.
9. Remove the left (when looking from the back of the system) AC power
connector assembly from the chassis.
Keep the cable attached to the connector assembly. Use a Phillips #2 screwdriver
to remove the screw. Set the end of the cable aside in the back of the system so
that the cable doesn’t interfere with lifting the power distribution board out of the
chassis.
Removing and Replacing Backplanes and Cables 149