Got an alpha 550 plus with a mystery fault c. The reps for harrisons in nz say its impossible to have such a fault code as they only have codes 0-9 and yet here it is. At the same time we are having a spindle fault detected error code on screen and I'm assuming they are related. It is fine on start up but as soon as you open the chuck guard it faults and can only get rid of fault by cycling power. Switch is good and have tried other ones with new wiring, still no difference