I just spent the last hour putting the finishing touches on a repair that I started way back when. Unfortunately, there’s nothing physically wrong with the lens; I had it in many pieces, far enough into the guts to find any physical defect, and there were none. So, I don’t know what’s wrong with the lens. It works fine in manual focus, and I’m tempted to sell it on ebay as such. then again, having a backup 50 is never a bad idea. Photo evidence (sorry for the crappy phone pic):
Up next: photos. seriously.