AMS is a complex electromechanical device with sensors, electronics, actuators, and mechanical parts.
Parts wear or faults are unavoidable during its long service. Regular maintenance will reduce the wear and increase the life of the printer.
There are many guides here that could help people to do service or change faulty parts.
AMS lite Installation Tutorial
AMS lite Body Installation Tutorial
AMS lite Spool Claw Installation Tutorial
AMS lite Feeder Unit Installation Tutorial