I got a broken A7 included in a classifieds purchase. It has the bottom center pin adjustment screw broken off inside the center post. I do not know of anywhere to get a replacement screw so I have not spent a lot of time trying to get the broken one out yet. Longshot I know but I thought I would mention it here and see if by chance someone knew of a source for one?
It's not a big deal as they are so inexpensive and its still useful to rob parts off of but I hate having a broken one, I simply can not have something broken and NOT try to fix it. The way I am wired I guess.
Getting the old broken center pin out may be fun

I'm looking at my center screw now (took it out)...it's basically a small slotted cap screw, if you took what was left to an industrial fastener place and matched the threads...if you have access to a drill press all you would have to do is cut the new cap screw to length and drill a hole through the center, easier said than done but with a good quality drill bit, very do-able...