I purchased the servo motor/cobbler kit for Lesson 8, installed Occ v0.2 on the Pi, soldered & wired the set-up on the breadboard. The python program appears to run without error and writes outputs to the files (active 1, delayed immediate (?), mode [servo], etc), but the servo motor doesn't move. The voltage is 6V, so it looks OK. The red lead is +6V, brown is grd, orange is connected to pin 18, and the grd on the cobbler is jumped to battery grd as shown in the picture. The servo motor output shaft is rigid and cannot be advanced by hand, so this seems strange. Is it possible the servo is bad? How can I troubleshoot the set-up?