Had same issue during attempted calibration. Mine was solved by fully seating the USB C connector on the bottom of the unit. The comments in this posting pointed me in that direction, so, thanks!
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Throwing another one on the pile here. A1, out of warranty, no AMS.
z axis homing failed; eddy current sensor signal is abnormal; toolhead is malfunctioning
Z axis movement is similar to others reported: up 20mm, down 10mm, up 20mm, pause, failure message, up 50mm, up 50mm, down 5mm, stop. If the whole process starts more than halfway up, then it will crash into the top. No visible obstructions, no apparent resistance either moving the arm manually or spinning the motor/pulley with a finger.
Hotend has been replaced, TH board has been replaced. Neither has made a difference in any combination. I only have a SS 0.4 nozzle and all bolts for it have been checked. Eddy sensor tape is in good condition with no exposed copper, leads measure 3.2 ohms on both hotends. All connectors, wires and pins have been checked on the tool head and underneath the base.
I’m trying to rule out the most recent firmware as the cause, but I can’t perform a downgrade, either. With files on SD card, install fails at about 50%. With the Handy app, install fails almost immediately, SD card in or out. I have tried with versions from 01.04.00 to 01.07.00. Brand new SD card formatted on the printer.
I’ll try to update if I can find a solution.
minus the flag of “eddy current signal abnormal” your issue sounds exactly like the USB-c connector [in the plastic sled thing] on the bottom being half plugged in. A true derp check, but maybe unplug and replug that in, making sure its fastened up while its connected.
That was the most recent thing I checked. I didn’t even recognize that as a connector at first, concentrating on the three obvious connectors right beside it. Even trying to produce more slack in the USB cable, there is no way to physically seat the connection more. It slides in with the expected soft click of USB C.
Now you’ve made me think of rotating it 180 degrees and trying again.
Yeah, that didn’t change anything, either. It did remind me that occasionally it will display ‘homing all axis’ and do nothing at all when I try to calibrate. Goes back to the normal non-working state after a reboot. I’ve seen it like 2 or 3 out of 20-25 times now.
Ok no worries, it wasnt mentioned specifically as a test so worth a shot. Hope you and support find the issue! That dance where it goes up Z but will never go further down Z than it started is real characterstic of that problem.
Had same problem as originally asked: Failed calibration due to Z-axis.
Following subsequent posts I went back to the USB-C and gave it some good shoves.
I was getting worried I’d need a return, Thanks - now working.
[It sure takes its time to calibrate.]
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Problem solved.
Hi,
Brand new user and A1 printer. I had the same problem. After repeated power on/off cycles and raising a ticket, I read the whole thread.
With power off:
I looked at the USB/Cable unit and saw a small amount of the USB-C metal connector.
I then unscrewed the USB/Cable unit and pushed the USB/Cable connector in a further 1 mm.
I then left the USB/Cable unit screw out/loose.
Then, with power on, I performed start-up checks (axis alignment, etc.) - it worked and is now performing all the other 1st-time start-up tests.
Summary: The USB/Cable screw-hole is in the wrong place - 1~2 mm too short; remove the screw and push it home by 1~2 mm.
Bambu Labs should consider redesigning the screw or fixing the location.
Good luck, and thanks to everyone who posted above.