Troubles using Marlin on Mega2560 + RAMPS 1.4

Hello everyone !
I have different troubles, but I think they are all linked :wink:

My config : an home made machine used to print (3D plastic) and cut (laser), powered by Marlin 2.0 on a MEGA 2560 and Ramps 1.4. My laser is a Nejetool (model 30W). I use the latest version of LightBurn.

  • The laser doesn’t stop cutting between two shapes (even if LightBurn has well sent M05 command !!). In the same try, the laser correctly stop itself after the two shapes. Same problem if I add Tabs to a shape.
  • I am not able to use PWM on the laser. M3 or M4, whatever the value or not sent after, switch the laser at it’s maximum … It seems logic because the laser TTL wire is plugged on the D4 pin. I think I should use D6, but the current is always at 1.48V on this pin (doesn’t react to M3/M4/M5 …).

I have three hypothesis :

  • Wrong configuration in Marlin
  • Wrong configuration in LightBurn
  • Issue(s) on my RAMPS or MEGA

Do you have any ideas ?
Don’t hesitate to ask me questions if needed :slightly_smiling_face:

Robin

In general I know lasering on Marlin is tricky business. What device type have you setup in LightBurn for the laser?

Thanks for the quick answer.
I’ve done it manually, and used the ā€œMarlinā€ choice.
I’ve changed my pins and I think I have a good result now !! I’ll confirm in a minute or so.

I solved the issue but I don’t understand why …
I changed de PWM pin from 6 to 5 on the board and it works fine now !
I think my PIN number 6 it ill … I have to investigate. For the moment I can use my laser for the Christmas Presents !

Do pins 5 and 6 both provide equal PWM capability?

I don’t know … I think yes, they both are on a zone used for servos

Hello, can you please share the firmware and wiring?

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