Turn the knob on the ammeter to its maximum and test. If the problem persists, proceed with the following steps.

1. Press the test button and check the reading on the LCD, the normal reading should be 8 mA.

• If the reading is lower than 8 mA,

1. Connect the wires of the laser tube cathode and anode.  
2. Press the test button again and check the ammeter reading.

• If the value is about 8 mA, replace the laser tube with a new, identical one.
• If the value is still way off the mark, replace the laser power supply with a new, identical one. 
• If the ammeter reads 8 mA the moment the test button is pressed, open the cover of the laser power supply (refer to the video).

2. Measure the voltage between the IN and GND terminals of the laser power supply across different power settings.

1. If the voltage readings turn out to be close,  the main board is faulty. Replace it with a new, identical one.
2. If the voltage readings do vary, the laser power supply is faulty. Replace it with a new, identical one.