I expect the cyclone needs cleaning. Remove the bin/cyclone assembly, release the base, empty debris into bin bag. Then remove bin from cyclone. Carefully remove the top 3 screws and remove handle part. Clean all the dust out, tapping the cyclone gently to clear the holes in the side. Carefully reassemble, making sure that the end of the long rod engages with the D shaped slot at bottom end. Hope this helps.
pete cridge, April 2006