I needed to relocate my older 990 Legacy Base today, so I loosened the signal wire thumbscrew. After a turn or two it came loose from the case and I heard something drop inside. The prospect of a metallic part bouncing off whatever sensitive and exposed electronic gizmos are in there were enough to make me panic and open the case, a task which proved easier than I expected. What I found loose inside were two 5/16" nuts, a black plastic collar, a steel flat washer, and a lock washer. These, of course, were the mechanical and electrical components necessary to remount and connect the thumbscrew.
Also laying in the case were these two plastic components -
I've reassembled the base without them and the entire Legacy system appears to works as it should, so I probably ought to leave well enough alone. Still, I'd like to know what these things are, where they go, and what they do. Any ideas?
- Mike
Imagine how I felt - I'm still trying to figure out which wire makes my train go frontward and which one makes it go the otherward. 
