Originally Posted by keithlester 
All except one of the contacts was open circuit. The springs form the electrical path between the contacts on the mounts internally, expanding and contracting to maintain the circuit as the helicoid is moved in or out. The springs each hang on to a row of small "L" shaped lugs on the contact strip directly beneath the rear mount. It really was a simple but fiddly matter of re-hanging each spring onto its lug. On my copy all but one of these springs had jumped, fallen or been shaken off the lugs. I don't intend to drop-test it to find out which.
If anybody intends to open theirs to fix it, may I recommend that you lift the lens off the mount, rather than lifting the mount off the lens. This will keep all the sprung pins in their correct postions in the mount. If any fall out, they appear to be completely interchangeable and it becomes quite obvious where they belong.
Seems a bit fiddly inside, "cheap" if you don't mind me saying so.
I took a sigma lens apart (it was junk and I was going to use the mount to convert a K to KA (but that is another story)
It had a very solid contact block, where all the pins and springs were retained even when you took the block off the back of the mount. This sounds almost like pandora's box, once opened you'll never get it all back in. As I said you did a good job.