There seems to be a disconnect between the shutter release and the magnet assembly that actually triggers the curtain. Depending on where the short is, this can be a pretty fixable problem. However, even when actuated manually, the shutter doesn't have the curtain tension to complete the cycle. Once the cycle is completed by physically moving the shutter curtain to its intended final position, the winding sequence is revealed to be out of adjustment, resulting in several turns of the winding lever to get the shutter back into position, at which point it again doesn't fire.