After several years (purchased new in 2007) of faithful worry free service, my Speedy has started to show some problems. When I wind the crown, it never stops winding (like it used to, to indicate it was fully wound). I can wind and wind, but it never stops. After I tire of winding (because it never stops) the power reserve lasts only 8-10 hours. Is it a problem with the mainspring? Can anybody shed any light on its potential problem(s) before I bring it in, just so that I can go to repair shop somewhat informed? Thanks in advance for your help.