I have a Schneider-Kreuznach APO-Symmar f5.6/210mm lens with a Copal #1 shutter. The aperture lever has become very loose. Its working and it will maintain it's position, but if it gets knocked into at all, like when I cock the shutter, it will move. If I take the lens off of the shutter, is there something inside the shutter that can be adjusted to tighten the aperture lever/ring?