1. Check whether the laser tube is intact. If not, replace it with a new, identical one.

2. Check whether the laser power supply can be energized. If it cannot be, troubleshoot as per The indicator on the laser power supply does not light up>>.

3. Check whether the potentiometer of the ammeter is at its maximum (if applicable).

4. On the panel, set the maximum and minimum power to 45%, press PULSE to fire the laser, and check the status of the laser tube and the laser power supply.

5. If the laser is functioning properly, then the previous power setting was too low, causing the laser tube to fail to fire properly.

If the laser fires but the power appears weak, see Weakened laser performance>> to troubleshoot.

If there is still no laser fired, then check the laser power supply.

• When the laser signal of the ammeter is always "OFF", short the laser control terminal port L and GND port on the laser power supply.

• When the laser signal becomes on, check the wiring between the power supply and the mainboard. If the wiring is secure, replace the mainboard with a new, identical one. If the laser signal is still off, replace the laser power supply with a new, identical one.  
• If the laser signal of the ammeter changes to "ON" when the pulse key is pressed, check the current value.
• If the current value is always 0-1mA, unplug the laser control terminal (6-pin terminal) on the laser power supply, then press the test button on the laser power supply or the test button on the external ammeter (if applicable) to check the current value.

• If the current value still falls into 0–1mA, see Ceramic resistor test>> to sort out the faulty component.
• When the current value reaches about 10mA and the laser tube emits the laser normally, measure the voltage between the IN and GND (as shown) port of the laser power supply control terminal with PULSE pressed (normally about 2V). If the voltage is normal, replace the laser power supply with a new identical one. If the voltage is too low, replace the mainboard.

• When the current value is about 10mA but the laser tube does not respond, replace the laser tube with a new, identical one.