hi ian,at a guess yourpressure switch is blocked with powder residue,quick repair remove the two screw's that are securing the top,then push the top from the front of the machine toward's the back to remove the lid,once lid is removed look into the machine & on the left of the m/c (looking from the front)there a white circular item with a clear 6mm diameter hose clipped on to it,remove this clear hose from the white circular pressure switch & blow down this until there's no residence,job done assemble in reverse order best of luck
steray
March 2008