I have a printrbot simple metal. The z stop has been causing all sorts of problems. I bought a new probe thinking the old one was bad and the thing went up but not down. So I got a new board after frying the old one and now I figured, let's see if a limit switch would work and.... Nothing. I have had this thing for a year and fooling with it on and off has got me nowhere. If you have any sort of help I'm willing to consider trying it.