Quoted from Sunfox:
So, to continue... turns out the right limit switch is working, and it seemed like the mech was binding on the right side of its arc.
So I removed it, and noticed that the wires feeding through the mech seemed to be pulling too tight. Adjusting those and re-installing it, I now see the real problem: the back of Smaug's head is rubbing on the rear ramp lane when he's turned about 90% to the right.
I'm not quite sure how to adjust this without breaking anything. I've already tried mounting it as far away as the screw holes will allow (minimum movement available) and he still hits. My Smaug seems to have a bit of an underbite, and the whole rear/top of the head could be pushed/bent forward, but I don't know how to do this without breaking something.
Talking to myself here... removed Smaug again, and unscrewed the 2 screws holding the back/top of his head from the front/bottom of the assembly.
I then added some thin shims (rubber bumpers) to the bottom beneath the screw holes, so that when the two halves are screwed back together, the bottom pushes out a little and the top thereby pulls in, hopefully giving it more clearance from the ramp.
Put it all back together... and presto! Full range of motion without contact, and both limit switches trigger normally. Adjusted his mouth to work properly with the new alignment, and now Smaug works great!
I also re-arranged the small wire on Smaug that scoots up around the metal baseplate, which had been ziptied at the factory such that it stuck up vertically and rubbed against the rotating plate, already causing some wear on the sheath.