Marc, Yuhang
Yesterday I tried to remove the 4 screws holding one of the 2 crystal.
Once they are removed, it is possible to access 2 set screws that fix the linear translation stage.
The 4 screws were really tight and I only manage to remove 3.
With Yuhang help, we tried to remove the fourth one without success.
In the end, we broke a screwdriver head inside the screw..
Fukushima-san from ATC helped us to remove it today.
After that the linear translation stage was replaced with a motorized one and the Soleil-Babinet is now closed with 3 out of 4 screws (need to purchase the broken one).