Dornbracht Shower/Tub Diverter Sticky

[leorob]

I have an older (25 year) Dornbracht shower/tub diverter and it has become hard to turn.
I'd like to take it apart and repair it.
There is no set screw on the handle and I would like to know how to take thing thing apart.
Any help?

 

[Jadnashua]

That graphic at the hub of the handle probably pops out, and the screw holding it in place is behind it. Could be a bear to get out.