Duet 3 6HC v1.01 motors stalling

Arkadiusz

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.

Phaedrux

Please share your full config.g and your homing macros.
Also share the results of sending M122 and M98 P"config.g" in the gcode console.
Verify that your motor currents are being set as expect by sending M906 and M913.

So X axis movement is fine, Y axis movement is fine, but X and Y together stall?

And when you drive the motors without the axis connected are you able to stall one the motor shafts very easily by hand?

Have you changed up the driver assignment? For example using unused drivers for X and Y?

Trying to isolate which driver may be causing the issue. Perhaps it's one of the Y pair.

Arkadiusz

@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

Phaedrux

@Arkadiusz said in Duet 3 6HC v1.01 motors stalling:

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.

So what driver number is stalling? Or is it all of them?

It looks like you have two spare unused drivers, have you tested those?

dc42

@Arkadiusz it sounds like a power supply problem to me. Send M122 a couple of times to reset the record of minimum VIN voltage; then command movements that cause the motor to stall; then send M122 again and look at the current and minimum VIN voltage in the report.