My trusted Pentax K-30 camera got afflicted by the stuck aperture problem. It's a known issue and the fix involves buying a part from ebay (or pillaging an other camera) and soldering it yourself, the camera is too old for warranty.
BUT, the good thing is that old manual lenses from the 70's and forward work in manual mode, as long as they have an aperture ring. I found a bunch of old lenses at goodwill for about 10€ each, some pretty good, some not fantastic.
















