A common question we get at Smoke & Mirrors is about how to diagnose if a water cooled CO2 laser tube needs to be replaced?
The above flow chart should helps with some very basic diagnostics. Replacing the CO2 tube in your laser cutter often feels like a simple answer, but very often alignment (the process of making sure the laser beam is bouncing off the mirrors consistently, in a straight and level 90 degree line from your tube to your lens and down to the work) is most often the cause of problems that look like tube problems.
You might find these videos helpful too!
Checking the interlocks on a laser cutter
A basic alignment check