I have replaced the roller pads, the memory card, the Flex shaft, the Z-truck assembly, the cover switch, the cut off wires to the cover switches, the head termination board, the FCC cable, and I went back and made sure everything was in correctly and tight. And Frank you are right the new enclosed switch went in easily and works well. When I do the sensor test I get Y axis movement recording but no Z axis recording and I switch cables around as the documents say to and there is still no Z Axis movement recorded. I think this is finally back to the original problem which was air carving. I have ordered a new Z motor mount electronic board. Not much left to replace eh?