At least the power seems about right 
. Is there somehow a possibility to test RTKB and / or the SOM alone. I saw in another post (DonvVito: Replacement for PCB or replace stepper motor driver), that the guy from the post tested the motor with, I think, a ramps (or similar) and could verify that the motors are still working. So I am looking for something similar to test the RTKB and/or SOM.
Thanks for the support