Then it seems like the electronics are probably OK. And 400 steps per mm ought to give you some motion, I think. However, typically, a Printrboard is 1/16 step, I think. So assuming 1.8 degree steps that's more like 1600 steps/mm. However, that wouldn't put it off.
Is Z homing working? Assuming you are homed if you put in the terminal something like:
Does it cause the Z axis to go up?