Common Servo Motor Failures
To ensure a successful servo motor repair, you need to be proficient in all areas of electro-mechanical repair and electronic repair. Here are some common problems we see;

Mechanical faults..
Bearings and bearing housings.
Grease, oil or cutting fluid contamination inside the motor.
Grease, oil or cutting fluid contamination inside the brake.
Shaft keyway or coupling failure.
Rotor magnet failures.
Out of balance rotors.
Motor brake wear.
Worn brushes or commutators (DC types).
Carbon build up (DC types).

Electrical faults...
Motor winding failures.
Brake coil failures.
Shorted wiring connections.
Broken wiring connections or faulty connectors.
Electromechanical tacho faults.

Electronic Faults..
Encoder output or position count faults.
Encoder alignment.
Encoder Memory faults or corruption.
Electronic Tacho faults.
Memory battery failure.
Resolver failure.
Faulty components on PCB’s.
Op-amp failures.
Driver IC failures.