If the mixer in the coolingtray is stopping when there are a lot of beans in it you might need to adjust the resistance of the motor.
Please find the motor that is driving the axle of the tray.
Remove the pin holding the crown nut. Next, take the small wrench from the tool kit and turn the nut clockwise.
Once the nut is tight lock it by bending a pin in the nut.
Now the tray should mix without problems even with a large batch of beans.