A.    Clean the contact plate on the plotter with a dry cloth.
      
      1.    Try installing the cartridge a little differently. Try the
            following:
            
            a.    Place the cartridge onto the mounting base making sure it
                  is flat against the back. Remove fingers from the cartridge
                  and lower the locking lever down.
            
            b.    If that doesn't work, repeat process, this time jiggle the
                  cartridge a little as the lever is being lowered.  Note:
                  The lever should go down easily.