Hi all. I have a gravermach that i haven't used for 7 months. Just fired the compressor up, switched on g mach and selected the handpiece i wanted and the normal hum/buzz came from the selected handpiece. However on pressing the foot control nothing happened and there was no hissing of air as i remember used to happen.Tried changing handpiece selection and again the selected handpiece showed sign or being connected but it was non responsive with foot control. The air outlet hose on the back of the unit has been removed and pulsed air is there, yet i can hear no hissing from the foot control. there are no kinks or breaks in the air hose. I would very much appreciate help. If you would like to look at some handpush engraving and diamond setting please look at my website www.cuttingedgejeweller.co.uk. Thanks in advance for your help. this is a great site with some very talented crafts people.