Is there a "how to" on this somewhere? Or, failing that, where's the best place in the USA to have one repaired? The one I have is stuck in the closed position. The winder won't move although if I press the little sliding button I can crank the winder backwards. Normally this cocks the shutter. It feels like it does cock the shutter and when the release is pushed there is a soft click but the shutter does not open and close.