ManiacDan
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[pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Thu Aug 17, 2017 2:27 pm

Good day everyone,

I have been having a lot of problems with my pre-assembled Prusa i3 mk2 (purchased pre-assembled right from Prusa shop). I'll spare everyone the long story and get right to the problem description:

There are 3 main "clues" as to what might be wrong:

1) During the "G81" Z calibration, the print head crashes into the center of the build plate. All other points are fine. This behavior happens regardless of PINDA settings. See video: https://youtu.be/e5NCyd5HsoM (It crashes into the bed in the first 4 seconds, then again at 0:33)

2) During X,Y,Z calibration, the bed motor repeatedly "knocks" against the frame as though it's attempting to go to a Y value the printer cannot support.

3) Most disturbing of all is this image. During calibration the printer displays:
20170811_103825_HDR.jpg
20170811_103825_HDR.jpg (2.02 MiB) Viewed 276 times
So I'm not sure what to do from here. There's clearly something wrong, and I suspect there's something wrong with the firmware on the device, but since I didn't assemble it myself and I'm still very new to this world, I wanted to get help from the forums first. Despite the printer being less than a month old it's been a week since I've heard from customer service (Though hopefully I can regain their attention here).

Thank you in advance everyone.

The output of Pronterface when running the calibration is below. The youtube video above was taken while this output was being generated.

Code: Select all

>>> G80 SENDING:G80 >>> G81 SENDING:G81 Num X,Y: 7,7 Z search height: 5 Measured points: -0.22583 -0.39250 -0.52583 -0.62583 -0.69250 -0.72583 -0.72583 -1.31028 -1.79009 -2.03358 -2.04074 -1.81157 -1.34608 -0.64426 -1.94083 -2.58617 -2.87716 -2.81380 -2.39608 -1.62401 -0.49759 -2.11750 -2.78074 -3.05657 -2.94500 -2.44602 -1.55963 -0.28583 -1.84028 -2.37380 -2.57182 -2.43435 -1.96139 -1.15293 -0.00898 -1.10917 -1.36534 -1.42290 -1.28185 -0.94219 -0.40392 0.33296 0.07583 0.24463 0.39019 0.51250 0.61157 0.68741 0.74000 >>> G80 SENDING:G80 echo:Enqueing to the front: "G28 W0" >>> G81 SENDING:G81 Num X,Y: 7,7 Z search height: 5 Measured points: -0.20667 -0.36759 -0.49870 -0.60000 -0.67148 -0.71315 -0.72500 -1.30444 -1.78788 -2.03211 -2.03713 -1.80294 -1.32955 -0.61694 -1.94056 -2.59535 -2.88893 -2.82130 -2.39245 -1.60239 -0.45111 -2.11500 -2.79000 -3.06917 -2.95250 -2.44000 -1.53167 -0.22750 -1.82778 -2.37183 -2.57282 -2.43074 -1.94560 -1.11739 0.05389 -1.07889 -1.34084 -1.39989 -1.25602 -0.90924 -0.35955 0.39306 0.13167 0.30296 0.44963 0.57167 0.66907 0.74185 0.79000 >>> G80 SENDING:G80 >>> G81 SENDING:G81 Num X,Y: 7,7 Z search height: 5 Measured points: 0.05583 -0.08046 -0.19074 -0.27500 -0.33324 -0.36546 -0.37167 -1.15407 -1.62870 -1.86515 -1.86343 -1.62352 -1.14543 -0.42917 -1.87630 -2.53318 -2.82796 -2.76065 -2.33123 -1.53972 -0.38611 -2.11083 -2.79389 -3.07917 -2.96667 -2.45639 -1.54833 -0.24250 -1.85769 -2.41083 -2.61877 -2.48148 -1.99898 -1.17127 0.00167 -1.11685 -1.38401 -1.44676 -1.30509 -0.95901 -0.40852 0.34639 0.11167 0.28657 0.43685 0.56250 0.66352 0.73991 0.79167 >>> G80 SENDING:G80 >>> G81 SENDING:G81 Num X,Y: 7,7 Z search height: 5 Measured points: 0.06000 -0.07120 -0.17620 -0.25500 -0.30759 -0.33398 -0.33417 -1.15093 -1.62183 -1.85455 -1.84907 -1.60541 -1.12356 -0.40352 -1.87454 -2.52896 -2.82140 -2.75185 -2.32032 -1.52680 -0.37130 -2.11083 -2.79259 -3.07676 -2.96333 -2.45232 -1.54370 -0.23750 -1.85981 -2.41273 -2.62063 -2.48352 -2.00140 -1.17427 -0.00213 -1.12148 -1.38936 -1.45300 -1.31241 -0.96757 -0.41850 0.33481 0.10417 0.27750 0.42611 0.55000 0.64917 0.72361 0.77333 >>> G80 SENDING:G80 >>> G81 SENDING:G81 Num X,Y: 7,7 Z search height: 5 Measured points: 0.06250 -0.07185 -0.18074 -0.26417 -0.32213 -0.35463 -0.36167 -1.15898 -1.64746 -1.89144 -1.89093 -1.64592 -1.15641 -0.42241 -1.88954 -2.57011 -2.87808 -2.81343 -2.37616 -1.56629 -0.38380 -2.12917 -2.83981 -3.14065 -3.03167 -2.51287 -1.58426 -0.24583 -1.87787 -2.45656 -2.67916 -2.54565 -2.05604 -1.21033 -0.00852 -1.13565 -1.42036 -1.49360 -1.35537 -1.00567 -0.44450 0.32815 0.09750 0.26880 0.41602 0.53917 0.63824 0.71324 0.76417
Last edited by ManiacDan on Thu Aug 17, 2017 3:19 pm, edited 1 time in total.

aaron.s5
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Thu Aug 17, 2017 3:13 pm

I would open the Rambo box and make sure all connecters are secure (they could have come loose during shipping).

I would also make sure belts are tight, X and Y are visually perpendicular and all axes are free to move without binding.

I would check that the X and Y limit switches are clicked when the bed and extruder go to those positions. This is the only way the printer knows where the ends are. If a cable or zip type is preventing those switches from being activated it will cause lots of problems.

Do you have a clean power source or do you live in a place with frequent brown-outs?

I would also check the connections on the ribbon cable to the LCD display (at both ends) and make sure none of the cables are crimped.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

If you solve your problem, please post the solution for others.

ManiacDan
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Thu Aug 17, 2017 3:27 pm

Thanks. I know...most of those words. I was hoping not to have to disassemble it, especially if that means further issues with customer service if it comes down to another warranty exchange.

All undersides and belts of everything are clear of debris and wires, nothing is crimped, and my power is clean.

I'll take it apart this afternoon if I have time (and the right tools). Thank you.

Oh is there a website or how-to that you know of that will help me take this thing apart and check what you suggested? This will be my first time "inside" a 3D printer.

ManiacDan
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Thu Aug 17, 2017 3:36 pm

I'm sorry, I forgot to mention: The bed is still flat according to the FOUR rules/levels I used to double-check. Also, this problem happened completely out of the blue, it just started one morning. I took a successful print off the bed, cleaned the surface, started a new print, and the head ground right through the PEI. It hasn't worked since. Nothing appears loose or wrong aside from the fact that the extruder presses hard into the center of the bed.

DoctorRudd
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Thu Aug 17, 2017 3:49 pm

Silent mode used while calibration?

ManiacDan
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Thu Aug 17, 2017 4:55 pm

No I never run in silent mode, that room is already loud. Is that recommended? It's the first I've heard mention of it.

aaron.s5
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Thu Aug 17, 2017 9:25 pm

No, it is not recommended, but could have been the source of the problem, which is why they asked.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

If you solve your problem, please post the solution for others.

bardiir
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Fri Aug 18, 2017 7:41 am

daniel.m41 wrote:
Thu Aug 17, 2017 3:36 pm
I'm sorry, I forgot to mention: The bed is still flat according to the FOUR rules/levels I used to double-check. Also, this problem happened completely out of the blue, it just started one morning. I took a successful print off the bed, cleaned the surface, started a new print, and the head ground right through the PEI. It hasn't worked since. Nothing appears loose or wrong aside from the fact that the extruder presses hard into the center of the bed.
Maybe you need to do an xyz calibration from the menu after reflashing the firmware. The garbled text could be a software corruption in the controller memory.

Otherwise, maybe the pinda probe cable has an issue, happened to me, in certain positions the printer would loose connectivity to the probe, so I needed to replace the cables as they were broken. Maybe that could lead to false measurements of the printer on some specific points and thus drive the nozzle too deep at certain positions.

ManiacDan
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Wed Sep 06, 2017 7:46 pm

bardiir wrote:
Fri Aug 18, 2017 7:41 am


Maybe you need to do an xyz calibration from the menu after reflashing the firmware. The garbled text could be a software corruption in the controller memory.

Otherwise, maybe the pinda probe cable has an issue, happened to me, in certain positions the printer would loose connectivity to the probe, so I needed to replace the cables as they were broken. Maybe that could lead to false measurements of the printer on some specific points and thus drive the nozzle too deep at certain positions.
Hey guys, sorry for the delay (I'm sure you were waiting with baited breath for updates). I performed a firmware update and I have a number of new clues, but I'm no closer to a solution.

CLUES:
1) PINDA is fine. It passes every test.

2) During the XYZ Calibration, the Y axis motor "knocks" against the printer housing, as though it's trying to go to a Y value greater than 250.

3) Auto-home works fine, but afterwards the y-axis motor remains engaged, grinding and whining like it's trying to force the bed past its zero point. The x-axis is harder to discern, but may be doing the same thing.

4) The end stops for Y and Z are correct, repeated manual tests shows that they're being detected properly by the system despite the head crashing through the bed and the bed knocking against its...end stop. So it's weird that it knows where to stop and doesn't.

aaron.s5
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Re: [pre-assembled i3 mk2s] print head crashes into center of bed ONLY, properly calibrated elsewhere.

Fri Sep 08, 2017 12:43 am

This is a long shot, by try re-flashing your firmware.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

If you solve your problem, please post the solution for others.

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