This is a just retrofitted CNC lathe machine, but it is not working without any alarms.
Use universal meter to check the switch power supply and found that there was no +24V output, and there was no any alarms.
This could be several reasons:
1- The power supply is broken or open circuit.
2- The I/O board or the I/C 2803 is shorted of the CNC controller.
3- Check the universal meter and see if it is broken or not?
In this case the power supply was working fine as long as unpin the CNC controller input port, check step by step then we found the IC 2803 was broken, change it then the CNC controller resumed.