In some photos the black object on the side appears to be a motor with shaft vertical. I looked through a number of sites and my thought is that this is the Selsyn unit used to remotely focus the lens: the camera operator had no way to focus it and it was done by another operator observing a monitor and adjusting the focus as required. The device above the Selsyn, if that's what it is, may be gearing and mechanical linkage attached to the lens inside. See attached:
http://www.tvcameramuseum.org/rca/1939fcam/1939fp1.html