Nottingham Space Deck and Space Arm question?

I have a Nottingham Analog Studios Space Deck with the Space Arm. At the pivot point, there is a set screw that the setup guide (as slim as it is) says "do not adjust." Well, I got this deck second or third hand and it has been adjusted....sooooo....does anyone have any info on just how the proper adjustment is achieved WITHOUT sending it to England???

Thanks, hope someone can help with this.