If it occurred twice with 2 boards that would indicate there is some fault with your hardware. Problem happens when you are trying to print, so lets narrow it down to heaters.

@Phaedrux

I disconnected the motors and tried each driver individually with a motor alone (not connected to axis). All 6 drivers behave in the same way. The Y axis stalls in the same fasion, the reason it worked so far is because its driven by two motors. I stalled them easily with my finger.

When both X and Y axis are driven together they are much easier to stall.

I also removed board and inspected it for any water condensation or debris - its perfectly fine.

I wonder why motors stall completely and wont turn again. On my 3d printers when I stall the motor it will lose steps until I release it and then continues to turn.

config.g console.txt homeall.g homex.g homey.g homez.g

I used this board for past 4 years and it worked like a charm.

However recently X motor started stalling and losing steps. Occasionally Z axis will lose steps as well. Y motors run without any issues.
Stalling happens always when moving X and Y axis simultaneously. And when driving X axis alone it happens at random.
Intermittently I am getting driver short to ground errors.

G code is exactly the same, I haven't changed anything for past 4 years.

Here is what I tried so far:

• Replaced power supply
• Replaced stepper motors
• Replaced all cables (motors, endstops) and crimped new connectors
• Checked if machine axis run smoothly
• Tried to run motors alone without driving axis
• Connected motors to different drivers available on the board

Effectively I replaced all electronics except main board (what a waste of time)
I checked all connections multiple times, and everything is connected correctly with no shorts (there was no shorts to begin with !)

I run axes at:
X - 4A
Y - 3.5A (two motors using 2 separate drivers)
Z - 2.5A

It seems to me that Duet cannot deliver sufficient current to the motors anymore.

@dc42 Never connect the input of a DC-DC converter to a heater or fan output. - I did exactly that, what might be consequences?

I will follow your advice, thanks for letting me know.

I guess I got lucky, 1st rule of engineering: If it ain't broke, don't fix it

Yes S1 and S0 works for me but Led it too bright I needed to dim it.

Anyways got this issue solved, I added step down DC converter between Duet and Led, now flickering is gone.

@bearer I tried all sorts of PWM values, I don't really need to dim them but I have to be able to turn it on and off with G-code commands. And I don't have any driver after duet, just a resistor

@taconite I cannot have this LED always on, I need to be able to switch in on and off with m106 commands.

I'm using duet wifi to build pick and place machine with bottom vision camera and led ring around it.

I have problem with horizontal lines on camera image and I suspect it might be caused by Led controlled by PWM from Fan2 output.

Is there any way to switch off PWM on fan and just have plain voltage control instead?

Thanks
Arkadiusz

@Veti I just printed calibration cube and it came out 3.5mm too short, missing bottom layers.
Z axis doesn't work until it reaches offset height I setup on E1: G10 P1 X0 Y0 Z3.5 U0

edit:
I removed offset from G10 command and instead in Cura in extruder2 start g-code I added:
G1 Z3.5
G92 Z0
This did the trick, now I have to find way to implement it in duet config file. It works fine but I prefer to not rely on Cura to execute this command.

You're right, adjusting offset on E1 doesn't mess printer in the way E0 does.
I swapped connections between E0 and E1 and it works fine now thanks.

Its very weird that E0 does this, I took me a while to figure out it was Z offset on E0 causing that.