I have a zoom lense made about 30-40 years ago and its missing and apature spring, or atleast the pin doesnt work and just flop around, yes its an old screw mount. I would like to know where in mass or mail out place i can get it fixed. it's manufactures by "Sun Optical" and marketed by "Aetne Optix". I would like to get the cheapest deal with good results. heres the front cover of the old manuel. (the apature is stuck all the way open because the pin isnt working)