etix

That's what I thought. I will probably start porting the changes from the Marlin_UM_Original_Plus to Marlin upstream and report how it works as soon as I find some time

Does anyone knows the current state of Marlin (upstream) running on Ultimaker printers? They are supposed to be supported but I really doubt it will work out of the box. In addition, I wonder how much non-backported changes were made since the fork took place. If anyone who knows can give some insight, it would be nice to get a clear picture of the amount of work required.

Few days ago I bought a 24v LED strip to add to my Ultimaker Original+ but after setting everything up on port J15 I wasn't able to control it. It seemed the firmware was crashing right after sending the M42 command. In fact it was a firmware bug, the issue has been fixed for the UM2 but not for the UMO+ yet so I built my own version that I made available on Github. This is the result: The intensity of the light can be controlled by PWM using the the M42 S[0-255] command. 0 being lit off and 255 being maximum brightness. To flash, just get the proper firmware in 115200 or 250000 baud and single or dual extruder and use Cura to install the custom firmware. Hope it helps

Just wondering, does Ultimaker have plans to rebase their firmware on top of the upcoming Marlin 1.1 for the UMO+? The code of the upstream seems to be much more clean and has some interesting new features.

Indeed @mastereto solution worked perfectly! Adding a fan did not help but adding M907 X1100 Y1100 Z1100 E1250 into the gcode fixed my issue. Yes, there was a small clicking noise at regular interval coming from the z-axis stepper. BTW I contacted the French reseller that told me this is a new but known issue with the new boards and they're investigating.

I have the exact same issue on my brand new UMO+ (with the white control board). All prints start nicely but after 2-3 hours the z-axis misbehaves (supposedly because of the heat of the stepper / main board) and messes up all my prints in the same way as yours. I don't know if you experienced the same thing but when the printer starts doing strings "in the air" it seems the bed is off 1-2 cm from the nozzle. I'll try to add a fan on the bottom of my UMO+ to cool down to the z-axis stepper + board tonight and see if I can see any improvement. But I suspect overheating is the reason since the board is really close to the z-axis stepper which can be very hot since there is no active cooling.