Hey there! I am Peter. For this build, I am using AR2.0 s/w with Aluminum kit.Working through the build, the J3 motor doesn't seem to move the arm much. The arm remains in the position of touching the J3 limit switch.I even tried connecting J3 motor to the J2 motor wiring to see if I was able to "jog" J3 via J2 + - buttons but it had the same result - not much movement.NOTE: With the system off, I am able to easily move the arm up and down. So, I can confirm that the arm joint is not stuck.Any suggestions on the cause and fix?