Odd Z axis calibration behaviour
So I started to see some mesh bed level failures, usually on the 3rd calibration point, about 3 days ago, probably around 60% of the time, this was on 3.1.1. I upgraded to the latest RC FW and saw the same thing, only 100% of the time. Downgraded back to 3.1.1 and now I'm seeing what is shown in the video. Basically the z height during calibration on the 3rd, 4th and 9th points is way off yet the calibration continues and finishes, if I try to print I'll always get a failure on the 3rd point during the beginning mesh leveling.
What changed before the problem started: Nothing, I mess around with my MK2 the MK3 I purposefully have left virtually untouched until today hoping to have something always reliable, haha right. Anyways today is the first day I moved the printer since I put it together ( months ago now ) and I did double check all axis belts and bolts which look good ( and pass self test )
Thinks I've tried:
* FW Versions: 3.1.1, 3.1.3, 3.2 RC2 ( All exhibit the same issue now)
* Checked all wiring, everything ( including filament sensor ) is wired correctly
* Reset calibration data multiple times, rerun XYZ calibration, this fails eventually and during the first 4 points the 3rd and 4th (front / back right ) points the extruder is up high like in the video, even so it keeps going through 4 points, improving points, then fails on the z axis calibration part of xyz
* Self test: Everything passes, that is except the filament sensor which tells me to check wiring, but that thing hasn't worked since day one so this is an old issue, just mentioning in case it's relevant.
Thoughts? I'm at a loss at this point... Never been a fan of mesh leveling, always seems to cause headaches...
https://photos.app.goo.gl/5bYf0JW5tYU4CsDB3
Prusa MK 2.25 (Downgraded MMU on MK2 with MK3 printed parts)
Prusa MK3 Kit
Re: Odd Z axis calibration behaviour
I think you have a broken Pinda wire, or a bad connection on the Pinda. When you move to the far right, it triggers right away, suggesting an intermittent connection.
Re: Odd Z axis calibration behaviour
How does one go about verifying this when checking the wires and connections visually all seem ok? Multimeter to a couple (which) wires from the pinda while moving it to and away from the calibration point?
Prusa MK 2.25 (Downgraded MMU on MK2 with MK3 printed parts)
Prusa MK3 Kit
Re: Odd Z axis calibration behaviour
Not sure.. but watch the LED. It's usually on when it is NOT close to the bed, and goes off as it approaches the bed (around 1mm away from the bed). See if this behavior is any different when it is on the far right (just move the x-axis to the right, and then move the Z-axis up and down). Come back with your report.
Re: Odd Z axis calibration behaviour
Yep, spot on mate. As soon as I move the X Axis past about 2/3rds to the right the pinda probe triggers, nice catch. I opened a support ticket yesterday afternoon but haven't heard anything yet, I'm torn on whether or not I want to strip the pinda wiring out of the thicker black sheath to see if I spot a breakage anywhere. The outer sheath looks fine, no sign or wear or breaking. At least at this point I have a reason for the odd behavior. Thanks a bunch!
Prusa MK 2.25 (Downgraded MMU on MK2 with MK3 printed parts)
Prusa MK3 Kit
Re: Odd Z axis calibration behaviour
Just an update/confirmation. I cut the pinda wire about 2" above the probe spliced in an old usb cable I had lying around and all is well. Thanks again
Prusa MK 2.25 (Downgraded MMU on MK2 with MK3 printed parts)
Prusa MK3 Kit
Re: Odd Z axis calibration behaviour
Glad you worked it out! Double check your other wires in that area too... maybe you had a bind somewhere.