Agie Mondo Star 50 z axis home problem

Hi. In my workshop we have a
Agie mondo star 50. Suddenly there is a problem
when i try to home the z axis. I always stop on
someting betwen 0.012-0.017 I tried to clean the
brushes for the motor but nothing happend. And i tried
to change the betwen the z and y module card(?)
But nothing happens. I get an error code e39.

Your Z axis limit/homing switch sounds like it is not working.
If you are going past the limit you are binding the Z axis
causing the E39. If you have swapped Z DMD07 with X or
Y, then it can only be a bad homing switch or a mechanical
binding in the Z axis leadscrew