First confirm that the laser power supply is working properly
Disconnect the laser power supply from the controller
Turn on the chiller and fill the laser tube with water without bubbles
Press the laser powers test (TEST) button
Under normal conditions, there is light in the laser tube, and the light spot that comes from the light exit, which is tested with cardboard to be sure it's normal
Determine whether there is air leakage by color
Normal color: pink
Color of the light when air leak occurs: darker, purple
To sum up:
If the laser tube does not fire after pressing the test button and there is popping sound, then the laser tube has air leak.
If there is light in the laser tube, but there's no light when you aim at a cardboard, then the laser tube has air leak.
Observe the color of the laser tube, it is pink under normal conditions; if there's air leak, the color is darker and purple.