I have inherited a wonderful Nikon F2 Photomic (what a wonderful camera) along with an MD3 Motor Drive. Alas no instructions. Figuring out the controls on the camera was a breeze. But having problems with the motor drive. Loaded fresh batteries - attached to the camera and all I get get is a constant whirring sound and will not fire. Only way to get it to stop is to set the frame counter to zero.

I suspect I am doing something wrong - can anyone help