User:
We have a CNC lathe machine with GSK980TD control system ,there is 421 alarm shows after turn on the power, sometimes it will be solved by restart the machine and works fine, but sometimes it can not be solved by restarting the machine, sometimes it shows both 421 and 422 alarm, could you tell us why? thanks.

CNCmakers Support:
421 alarm means there is AC servo driver problem, please kindly check the driver.