The back shutter should always be closed in normal use, except when firing the shutter, so when you take the back off, the shutter will be closed. I missed out a step in the firing of the shutter -see the article about the 500CM at http://www.djcphoto.com/index.php/hasselblad-500cm/ The 501CM is similar in the sequence. The article is an interesting read.
If the back shutter is sticking, then the camera ought to be serviced. What part of the world do you live?
If the back shutter is sticking, then the camera ought to be serviced. What part of the world do you live?