1. The easiest way: reinstall the software( pls note, before reinstall needs to remember the parameters).
2. Checking the driver board whether is burned or not， checking the driver light in the control cabinet,usually green light is working, red light is unnormal.
3. Checking spindle circuit whether has short circuit or not
4. Checking the U V W wires on the inverter whether has connected well or not.
5. Whether the leading wire of spindle is snap or not.
6. Checking the U V W wires on the inverter whether are broken or not.