Klipper Crashing when Homing Z

[capnzosima]

Running a 2.4 350 based on the LDO kit. Has been printing successfully for a while.
Just did a bed mesh recalibrate (I was seeing some first layer issues on one part of the bed)
After restart, I can no longer home the Axes without the printer ding emergency shutdown.
X and Y axes home correctly. Toolhead then moves above the sexbolt, and then immediately does a forced shutdown.

Any debugging steps you'd recommend?

 

[Christian]

Have you checked the log file? Usually it gives an indication why the shutdown happened.

Also check the cables, when one is broken it could be that at some positions it causes a shortcut.

 

[capnzosima]

Which log files in particular - I looked in klipper and moonraker logs. Is there another I should be looking at?
I'll check the cables.


After a few reboots and manually jogging gantry, Now I'm getting: Unable to read tmc uart 'stepper_z' register MSCNT once it hits the sexbolt.

 

[Christian]

Look at teh Klipper Log. Should be the last entry after the shutdown.
When a cable to the temp sensor has a problem, the entry could look like "MCU 'mcu' shutdown: ADC out of range"

 

[capnzosima]

OK here is what I think the error is:

Unable to obtain tmc stepper_z phase
Unable to read tmc uart 'stepper_z' register MSCNT
Unable to read tmc uart 'stepper_z' register MSCNT
Unable to read tmc uart 'stepper_z' register MSCNT
Pausing toolhead to calculate stepper_z phase offset
Pausing toolhead to calculate stepper_z1 phase offset
Pausing toolhead to calculate stepper_z2 phase offset
Pausing toolhead to calculate stepper_z3 phase offset

 

[Christian]

Does it also shutdown when you manually query the endstops? I would check the wireing of the Z-Endstop.

 

[p.warren69]

I'm following as I have a simular issue, when i go to home it raise the z like 10mm then shutsdown - no z or y motion. I can buzz ALL the steppers OK,
Queried the endstops several times - no issue. HELP

 

[capnzosima]

I get no errors when checking the endstop states, or when manually pushing the endstop. The issue seems to be with the Z Stepper

I'm seeing variable results. Sometimes I get this error when it lowers all the way to the z endstop:

Unable to read tmc uart 'stepper_z' register MSCNT

More commonly I'm seeing a crash as soon as it tries to LOWER the gantry

TMC 'stepper_z' reports error: GSTAT: 00000001 reset=1(Reset)
Once the underlying issue is corrected, use the
"FIRMWARE_RESTART" command to reset the firmware, reload the
config, and restart the host software.
Printer is shutdown

I'm running an LDO build with the Octopus MCU. I've looked at the underside and I'm not seeing any obvious loose wires. Any more specific ideas where to look?

 

[capnzosima]

Hmm possible new theory - when playing with the z steppers with power off, I can pretty easily roll the wheels on 3 of them to get the z-axis to move up and down. But the fourth (Back right one when looking at the front of the machine, will not move at all by hand. Perhaps it's resistance is too high?

 

[Christian]

Hmm possible new theory - when playing with the z steppers with power off, I can pretty easily roll the wheels on 3 of them to get the z-axis to move up and down. But the fourth (Back right one when looking at the front of the machine, will not move at all by hand. Perhaps it's resistance is too high?

Sounds like a broken motor. But to double check, I would disengange the motor from the Z-Drive and check if the Z-Drive moves without resitance. Bearings also can break.

 

[Christian]

I'm following as I have a simular issue, when i go to home it raise the z like 10mm then shutsdown - no z or y motion. I can buzz ALL the steppers OK,
Queried the endstops several times - no issue. HELP

Have you checked this message of your Log-File?

Transition to shutdown state: MCU 'mcu' shutdown: Timer too close
This often indicates the host computer is overloaded. Check
for other processes consuming excessive CPU time, high swap
usage, disk errors, overheating, unstable voltage, or
similar system problems on the host computer.

 

[ah2049]

I get no errors when checking the endstop states, or when manually pushing the endstop. The issue seems to be with the Z Stepper

I'm seeing variable results. Sometimes I get this error when it lowers all the way to the z endstop:

More commonly I'm seeing a crash as soon as it tries to LOWER the gantry


I'm running an LDO build with the Octopus MCU. I've looked at the underside and I'm not seeing any obvious loose wires. Any more specific ideas where to look?

I’ve found that loose wires and sketchy crimps aren’t always obvious on visual inspections.

If your Z steppers aren’t hardwired, you could try swapping stepper wires between two of them, then see if the problem follows the wires. You can do the same with the stepper drivers as well.