1. The water level switch is broken.
2. The high voltage wire is broken
3. The laser tube is broken or burnt
4. Laser power is cut off.
5. No water circulation, including clogged water pipes and non-functioning water pumps
6. The water protection line is broken or the contact is not correct.
7. There is no 220V input to the laser power supply.
8. No signal from the laser power supply. The signal line is broken and the contact is not good. The relay that controls the light emission is broken. The plate is broken and the welding of the wire is not good either.
9. Second online axis is blocked.