Spindle motor runs as soon as machine power on

The Spindle motor start to run as soon as turn on the CNC machine power, with any key pressing or G code command.

Normally this problem need to check below:

1-      Could be the IC2803 inside the CNC controller breakdown.

Solution: change the IC2803 or change the CPU board of the CNC controller.

2-      Relay or contact terminal of the contactor stuck.

Solution: change the relay or contactor.

3-      Wrong wiring.

Solution: Check the wiring and correct it.