Laser not turning off when Pause or Stop is hit

I recently added a laser (4.5W diode) to my MPCNC running Marlin 2.0.9. I have a problem with the laser not turning off if I pause the job. If I hit Resume the job starts back but the laser turns off and stays off. I have read several post in this and other forums about laser not turning off but have not been able to solve my problem. Lightburn 1.2.01 using Inline Mode. What does Lightburn send when pause or stop is selected? I know M5 will turn off the laser. Also the job will run great as long as I don’t Pause or Stop.

I’m not certain about this for Marlin. Can you enable the “Show all” toggle in Console and try pushing the pause and stop buttons during a job? “Show all” might reveal what’s being sent to the controller.

Ok, I did a quick test and this is what I saw in the console:

Starting stream
G0 X2.529 Y0.203 F0
Layer C00
G1 X0.018 Y-0.03 F600 I S12.8
G1 X0.027 Y-0.019
G1 X0.033
G1 X0.084 Y0.009
G1 X1.243 Y0.153
G1 X2.308 Y0.299

G1 X-0.383 Y-0.682
G1 X-0.445 Y-0.766
G1 X-0.488 Y-0.827
G1 Y-0.104
G1 X0.007 Y-0.039

G1 X0.126 Y-0.42
G1 X0.152 Y-0.414
G1 X0.173 Y-0.401
G1 X0.192 Y-0.382
Job halted
Stream completed in 0:22

Even though I see M05 is sent Marlin doesn’t take the command.
I can send M3 S20 and the laser comes on, then send M05 and the laser turns off. So the M3 and M5 commands seem work but when sent from the console. Puzzling.

Perhaps the buffer is getting overrun and are being lost? Maybe try lowering baud rate or use synchronous transfer mode to see if that makes a difference.

Synchronous and buffered seem to do the same thing. I ran same job from sdcard in controller and did almost the same thing except Stop did turn off the laser. I have accepted fact that pause and stop will not be functional in my setup at least when using Inline Mode. Not a big deal really, just need to be aware of issue so I don’t let laser get in trouble with burning something. Thanks for your response.

Exactly same problem here.
Laser keeps on when paused but turns off when resumed.

When you look at the commands in the console, Pause does generate a M5 but marlin doesn’t receive it. Then when you resume marlin takes the M5 and turns off the laser. I don’t know how it works with the other two modes. I just don’t use pause or stop.

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