Thanks for the help. Ulf, you are right, the lens is not OK.
I played a bit with the cable release and find out the the screw shows red ring but at this position the screw shake too much- probably to much use-and therefore this not function well. It fuction only when I fix the screw with my hand. I think the former user need this too much. I get the lens from a commercial dealer on the bay, but it is some moth ago, so I think I must take a look for somebody who can service it. But for some pics I can go this way first.
Another question: How is the performans of the 75 shift at you when using digital?
I made only few pics, but my first verdict is that the lens is pretty soft on my Leaf 12. OK, I dont expect that the lens will be as sharp as digitar 72 mm, but it is also much wors than Super Angulon xl 72 mm, that I also tested. Also the standart Mamiya rz67 lens 110 mm perform really good, perfect sharpness at 11. The Mamiya shift 4/50 mm from 645 system perform also much better than my 75 mm.
Maybe is something wrong with my copy?
What are yours experienses?