Move the Muse so you can access the right side panel.
Unscrew the 4 screws in the middle removable area and remove the panel
Remove the 6 pin connector by pulling it gently out of the slot; be careful not to bend the pins. By removing the 6 pin connector, all protections such as the lid and the water interlocks are overridden.
Ensure you have water flowing through the tube and the lid is closed as these are no longer tested.
Hold the Internal Test Fire Button for 5 seconds and see if the tube turns pink or white. If it does then the laser power supply likely has no issues.
If the tube doesn't change color at all, then it is likely a broken tube or a bad power supply or both.
Apply some thermal label sticker paper to Mirror #1 and press for another 5 seconds to see if there appears any burn marks on the thermal paper.
If you have no dots but the tube turns pink your laser tube needs replacement and your power supply is likely ok.
If you do have a burn mark then your tube is likely fine and your power supply is likely fine.
If you weren't getting any burn at all with the 6 pin connected and running a job but it works with the test fire button, you likely have the water sensor malfunction eg it's connected backwards or a lid switch problem as the other conditions are the same.