The pressure chamber is blocked. If you don’t know where the chamber is then remove the table top and locate the pressure switch, it will probably be round in shape and about 3 to 4 inches across. It will have a few wires attached plus a small bore air hose. Follow the hose down and it will be connected to the chamber. Remove the pressure chamber from the machine and clean it out thoroughly. You could blow down the air hose but that will only clear the blockage for a very short time.
casper......www.selfix-uk.co.uk, March 2010