The fault on the tool post may be due to the breakdownofmachinery, electrical as well as control system.
当刀架出现故障时，可能是机械原因，也可能是电气、 控制系统方面的原因。
2
"Machinery and parts", "benchwork technics" and "machine tool maintenance and breakdown elimination" are main curriculum for benchwork of machine repaires specialties in technical schools.