I had this kr 10 super from my great grandpa, and on one occasion it decided to jam itself after the last frame. Mirror is still up, iris arm is still active and the shutter is 2/3 the way up the frame. Cocking arm doesn’t move and shutter button doesn’t do anything. Batteries were ok, but I don’t know if I should try and fiddle around the camera Willy-nilly . I have a bit of camera repair experience, but if there’s anything that rings anyone’s bell I would like to know. Thanks!