Lulzbot Mini startup/auto-level fail - around probe points

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idcrook
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Lulzbot Mini startup/auto-level fail - around probe points

Post by idcrook » Sun Jun 10, 2018 8:44 pm

forgive me if I was unable to locate a thread with someone else having a similar problem.

my Mini started failing in startup/bed leveling. Once it gets to the part of the startup sequence where it probes each of the corners, the print head never descends but rather _ascends_ at each corner, and sets it's initial z-height at that far height about the bed, making it impossible to do any prints.

This happens on .gcode that was successful in the past, always with the same result, and I've tried all sorts of things short of swapping replacement print head. This is a Lulzbot Mini, with a v2.1 extruder head.

here is a youtube, as a video is worth a thousand pictures, or something like that

Short vid of Mini bed leveling fail

trying embed too



The symptoms suggest to me that perhaps there's a "short" (always closed) in the continuity/level point sensing? but I do not know what to do with that.

I would be grateful for suggestions or next steps.

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piercet
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by piercet » Sun Jun 10, 2018 9:39 pm

That's looking like both z axis motors are reversed, the reverse axis switch is set in firmware, or rare but possible the Rambo board is shorted and going the wrong way. If you are under warranty I would call support.

idcrook
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by idcrook » Mon Jun 11, 2018 6:24 am

I had a similar thought earlier. However, manual controls, as well as most of the sequence is performing as normal, so I am unable to understand how it could be z-axis motors are reversed?

It looks to me as if the "search" for contact on the auto-level routine comes back as "true"/"circuit complete" immediately each time/everywhere, right?

Galadriel
Aleph Objects | LulzBot
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by Galadriel » Mon Jun 11, 2018 11:58 am

Did you happen to update your Cura software recently?

kmanley57
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by kmanley57 » Mon Jun 11, 2018 1:46 pm

With an Ohm meter measure between the extruder nozzle and one of the steel washers of the bed with the power cord unplugged. Low reading means your board is dead, should be around or greater than 5000.
I will express my CRAZY ideas at any time! So you have been warned. None of my opinions are Lulzbots and can be wrong at any second.

idcrook
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by idcrook » Mon Jun 11, 2018 3:27 pm

I tried this
kmanley57 wrote:
Mon Jun 11, 2018 1:46 pm
With an Ohm meter measure between the extruder nozzle and one of the steel washers of the bed with the power cord unplugged. Low reading means your board is dead, should be around or greater than 5000.
measuring with a DMM in Ohm mode:
- washer to washer : 2.4 Ohms
- washer to nozzle on print head : 5M Ohms to 10M Ohms

I am not familiar with details of extruder wiring or circuitry, but is it possible that the wiring for the sense path got internally shorted? Close inspection of the affected v2.1 extruder has what appears to be ruffled red insulation— near to where it “connects” to hot end...

idcrook
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by idcrook » Mon Jun 11, 2018 3:31 pm

Galadriel wrote:
Mon Jun 11, 2018 11:58 am
Did you happen to update your Cura software recently?
I use an octoprint/octopi setup on the Mini. The same .gcode’s (have prior printed successfully) all exhibit this problem.
I also tried a direct streaming connection from recent Cura (macOS) and it also exhibited same undesired behavior.

kmanley57
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by kmanley57 » Mon Jun 11, 2018 5:00 pm

what is the result of M119 in the terminal window of Octoprint. (with the X/Y sitting in the middle of their travel area. So the X/Y do not show as triggered.)

If you show a triggered state for Z min then your RAMBo has died.
I will express my CRAZY ideas at any time! So you have been warned. None of my opinions are Lulzbots and can be wrong at any second.

Galadriel
Aleph Objects | LulzBot
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by Galadriel » Tue Jun 12, 2018 10:25 am

idcrook wrote:
Mon Jun 11, 2018 3:31 pm
I use an octoprint/octopi setup on the Mini. The same .gcode’s (have prior printed successfully) all exhibit this problem.
I also tried a direct streaming connection from recent Cura (macOS) and it also exhibited same undesired behavior.


Sorry I should have been more specific, the reason why I asked if you had updated your software recently is that if you have upgraded from an older version of Cura this could just be an issue of needing to clear your cache. The old Cura had different start and end gcode and we have found that if the old gcode is imported into the new Cura when you flash the firmware it can cause the issues you are seeing. If this sounds like it might apply to you I have included a link to how to clear your computers cache for the MacOS.
macOS: https://www.lulzbot.com/learn/tutorials ... tion-macos

idcrook
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Re: Lulzbot Mini startup/auto-level fail - around probe points

Post by idcrook » Wed Jun 13, 2018 12:44 pm

kmanley57 wrote:
Mon Jun 11, 2018 5:00 pm
what is the result of M119 in the terminal window of Octoprint. (with the X/Y sitting in the middle of their travel area. So the X/Y do not show as triggered.)

If you show a triggered state for Z min then your RAMBo has died.
Sending

Code: Select all

M119
with the head positioned roughly in the middle of the build volume, I do indeed get Z_min triggered.

Code: Select all

Send: M119
Recv: Reporting endstop status
Recv: x_min: open
Recv: x_max: open
Recv: y_min: open
Recv: y_max: open
Recv: z_min: TRIGGERED
Recv: z_max: open
Recv: ok P15 B4
I think I am going to swap out the v2.1 extruder (I have an old one I can swap in) just to verify that its not internal to it.

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