I hope someone can help me here. I'll try to explain my problem as best I can and hopefully it will be an easy fix.
A few days ago my printer would not home correctly. Whenever I try to autohome my printer, the y and x axis home ok, but the z axis stays where it is (actually moves up a few mm and stops). For example, if I move the z axis up 100mm to clear nozzle, etc and then auto home,the printer will set the position of the z axis to where I moved it to. When I check the settings in the screen it has set it to zero.
I have tried various flavours of marlin and they all do the same, so I am leaning towards a hardware issue, but will be happy to be proved wrong as long as I get a working printer again.