I have a system containing a robot arm attached to a circular CT scanner. The base of the robot arm is fixed, and I want to rotate the scanner around an axis (axis 4). However, when I go to the rotate movement tab, I select 'About Entity', pick axis 4, and when I try to rotate the scanner about it...it doesn't work. The goal is to rotate the scanner about its central axis (as if someone were getting an xray). I attached my .sldasm file below. Please help 

EDITED BY MODERATOR: Moved to the Assemblies space. Please post to the appropriate space when one exists. Also, when making corrections, please use the Edit function on your original post (upper right corner) instead of posting follow up comments. I have made the corrections and deleted the two follow up comments.