I get this is old, and resolved (ish). However, I think I found a solution to the constant clicking. I was having the same problem, for some reason my nib got stuck down and even after replacing it, it seemed the component beneath was still stuck. After unscrewing the top part (which required pliers), I found that the plastic holding in that component had been deformed, and was holding it down. I used pliers to tear off the upper part of the plastic, releasing it and allowing the pressure when hovering to return to ~20 or so (I am using the 680s, which uses the same pen, and has 2048 pressure levels). Unfortunately, when taking the last bit off to try to reduce it to 0, I accidentally broke the wire coil just below that, rendering the pen useless. I would suggest using a knife instead, and not getting so overzealous.