My control wheel and and button also fell off my JVC GR-DVM 70 I am going to try to glue the wheel back in place. I will let you know how this works. It seems like it should work since the button appears to have been "snapped" in place to begin with. I think years of rotating the wheel just wears it loose. I always hated that stupid wheel anyway, it's very difficult to use even when it works.

After about four years of faithful service, our DVM70 also lost the selector ring and the button tab. It will be a part that needs to be ordered from JVC. So I opted to cut out a piece of projector transparency sheet to the size of the ring, place it over the ring/button and tape the wholw thing with clear scotch tape to the camera. It's not pretty or a perfect fix, but the camera works again. Because of the transparency circle, the tape is not sticking to the ring or the buttons, but trapping the ring and the button in place while allowing it top be turned. So far it has worked 6 months. Once this fix fails and the camera can't be used anymore, I'm buying a Sony.