z Axis Noise Problem Solved
I was periodically getting strange buzzing noises, particularly when the z Axis was making long adjustments. Used a stethoscope to find the source of the noise, and it turned out to be the front panel electronics! The LCD screen just hangs off its header connection to the PWB, and it was rattling against the PWB. The PWB is held in place with just two screws (both were tight), and the other side was banging against the loose board supports and the loose external case. All-in-all, many rattles, excited the the seemingly courser z Axis stepping. I have to fault the design, because supporting anything with connections that are all in a straight line is poor engineering practice. Electronic headers are not stiff enough, acting like a hinge instead of a sound mechanical support. Same for just two screws for the PWB. I solved the problema by putting in felt stickies where needed, and all of the noise went away. I don't know if the factory assembled printers are any better, but the build instructions for my kit had no provisions for addressing this issue.
...there are only 10 kinds of people in this world--those who know binary and those who don't...
RE: z Axis Noise Problem Solved
Whenever I read PWB I chuckle ... we always used ECB or PCB in the industry. Etched Circuit Board or Printed Circuit Board. I never once came across the term Printed Wiring Board until long after I moved on from engineering.
As for LCD issues, there does seem to be an abnormally high failure rate in the LCD. Perhaps you've discovered a root cause. Thanks!