I seem to be without operational power feed on my 16". I am not sure how to troubleshoot it. The star knob spins when not engaged and I can engage the selector and tighten the star knob to the point that I am moving the carriage or crossfeed by manually turning the star knob but she doesnt go under power feed! I cant find anywhere to read up on how to make sure it's in adjustment. I am not sure I have the star knob center screw set correctly either since it moves around a lot.