The electric current flowing when driving the motor is irregularly large.
Encoder cable is damaged.
Motor cable is damaged.
Check points and solutions :
Check if the Carriage Unit is correctly installed. Check if there is some foreign material on the driving section of the Carriage Unit. Check the connection between the CR Encoder and the Main Board Assy. Check the connection between the CR Motor and the Main Board Assy. Replace the CR Encoder Sensor. Replace the CR Motor.