I would say your friend may be correct, could also be a broken wire or loose connection. Are their connectors at each end (near stepper and electronic box)? If so, I would try disconnecting the cable at each end and check for connectivity on each wire using an ohm meter. Depending on the stepper and driver, there could be 4, 6, or 8 wires in the cable.
If the cable is ok, next thing upstream to check is power feed to the stepper driver from power supply.
What stepper driver is being used. There are certain stepper drivers that are frequently used on Chinese CNCs that are notorious for going bad.
If the cable is ok, next thing upstream to check is power feed to the stepper driver from power supply.
What stepper driver is being used. There are certain stepper drivers that are frequently used on Chinese CNCs that are notorious for going bad.