Problem solved:
In fact, the actuator of the center trough sometimes got caught on the metal bracket of the bAll kickout and was therefore wrongly always closed - this happened not always which made the search really tricky. I just had to bend the actuator a bit and everything works fine again
In fact, the actuator of the center trough sometimes got caught on the metal bracket of the bAll kickout and was therefore wrongly always closed - this happened not always which made the search really tricky. I just had to bend the actuator a bit and everything works fine again