Thank you. Fortunately I did not touch the sealed screws, found and read the instruction at Sinar.ch first.
I am a stupid and inexperienced amateur eager to spend the January Christmas vacation shooting paintings. And I am envious , a lot of LL forum members praise their dealers here. I have zero support from my Sinar-Bron guy here in Moscow, and the Phase One dealer is even worse. LL became a source of knowledge and real world experience for me.
Rainer, thank you for your help and very interesting posts here.
in any case i was using a 54h and mounted the contax adapter. it has 4 screws to mount the adapter.
the other 4 screws you see in the back itself are the adjust screws for the sensor itself. me i was clever enough to open them till the sensor was totally dejusted and after that seeing my error....... and having to send the back to sinar for new adjustment.