hello, I'm not sure if this is the right section of the forum for this question, but here it is. Twice now my aperture on my Nikon D-80 has stuck, and on the little top screen where it shows what aperture i have selected, it's blank, it shows 'F--' and i cant choose an aperture and it wont take any pictures... but then after a while i'll come back to my camera, and it will work properly again. Has anyone had this problem? or does anyone know how to fix it?! please help! thanks!!! Jeff B.