I think I said before that I "liberated" this fixture because the students kept hanging it upside down. The label on one side of the lens tube was affixed upside down at the factory. So much for quality control in 1979!
Until the SourceFour™ in 1994, this was my favorite line of ERSs. I still prefer its lamp alignment over all others: completely tool-less, every lamp change requires a peak-cosine adjustment, and the joystick is the simplest I've ever used. Strange that the Photometrics Handbook doesn't have the entire line of these--I wish I had the original cut sheets to send to Mr. Mumm.
I hate those lights with a passion...there is no eaiser light to knock out of alignment, you sneeze and the thing needs to be benched. Not to mention the fact that if you happen to accidently unscrew the barrel knob to the lens train while in the air its next to impossible to get back in.