I was trying to reduce the backlash in the final three joints, and
somehow, I got joint #6 totally bound-up and I couldn't turn it at all.
I'm sure glad I have TWO arms.
First, I needed to uncouple the driveshafts from the motor.
This is a tight fit, and the couplers keep turning while you
try to get them unscrewed since the last four joint-motors
don't have brakes on them.
Are you getting the idea that the Star Trek folks in charge of
creating the Borg worked on a Puma 560?
And the arm going back tobether.
Everything works fine now, and this wrist actually has
perfectly good backlash.