I am able to control my MPCNC and laser in Repetier without issues. However, I can’t get Lightburn to activate the laser. I can move the MPCNC X and Y coordinates, but when I hit button to test fire, nothing happens. When I play a file, the machine moves around but does not fire laser. I remapped pins in Marlin using the fan. Selected M106/107 for controlling laser in Lightburn. Still nothing.
No, that line is M106 (laser on) S255 (power value). P0 appears to be “tool index zero”, but that’s the default, so it shouldn’t be required. (And, I have seen it before - we even support different tool indices, I just very rarely use Marlin)
Draw a box in LightBurn, and click the ‘Save GCode’ button, then look at the resulting file in a text editor and compare that to what Repetier generates. There’s nothing magic here - if you compare the GCode from the two programs it should be easy to see what’s different between them.