X-axis fails self-test  

RE: X-axis fails self-test

try 'Auto home' and try again. 

when the printer is switched on, it has no idea where the print head is...     so maybe this is the initial cause. 

this is the same reason why the Z axis will only go up, after switch on, because the printer assumes that the extruder is at Z :0.0 where ever it is, until the user, or the gcode performs an auto home!

another possible issue, is if the X axis does not move smoothly, it may prematurely sense that it has reached the end of travel. this can be caused by the X axis back plate being tightened a little too much, or by lack of lubrication, or something restricting movement    cable tie nuts are often an issue here, preventing proper homing of the X carriage.

regards Joan

RE: X-axis fails self-test

What is Auto Home suppose to do?    It moves the print head all the way to the right up to the Z-axis tower  Why to you think that will solve the problem?

RE: X-axis fails self-test

turns out you were ON THE RIGHT TRACK with the note about cable ties! .    The x-axis selftest failures started after I replaced the nozzle heater, which meant removing and reattaching the wires.    The cable ties weren't in the way, but  wires were pulling on the print head, giving the stepper motor algorithm a false signal that it was at the end of travel.    This is one place where Prusa really cheaped-out.  It should have used proper limit switches.  instead of software.  

I should mention that trying to put all the print-head cables back in the fabric sleeve, and then secure them was an exercise in frustration.  The cable-management on the Mini is a disaster.  

Anyway, points to you for suggesting the cable ties.

Not entirely "cheaping out" by prusa

Posted by: @focus-research

turns out you were ON THE RIGHT TRACK with the note about cable ties! .    The x-axis selftest failures started after I replaced the nozzle heater, which meant removing and reattaching the wires.    The cable ties weren't in the way, but  wires were pulling on the print head, giving the stepper motor algorithm a false signal that it was at the end of travel.    This is one place where Prusa really cheaped-out.  It should have used proper limit switches.  instead of software.  

I should mention that trying to put all the print-head cables back in the fabric sleeve, and then secure them was an exercise in frustration.  The cable-management on the Mini is a disaster.  

Anyway, points to you for suggesting the cable ties.

 

It's not "cheaping out" it's a simplicity thing. Endstop switches are another part in a system that can and will one day fail. Removing them allows the printers to be less complicated.  They could have saved a lot of money by not using trinamic drivers and using limit switches instead.

I've used a lot of different printers and let me tell you, limit switches are not as useful as current monitoring. The major benefit is crash detection. It's a bit buggy on older printers, but being able to detect issues and highlight them really help when you're troubleshooting things. 

lack of limit-switches compromises reliability.

I've worked as a professional engineer on  a wide variety of products with  both linear and rotational actuators, including medical equipment where as you can imagine, reliability and repeatability are paramount.  If a junior engineer had come to me and suggested calibrating the travel by running a motor until it fully binds, they would be looking for a new job the next day  Optical interrupters used as limit switches are quite inexpensive and  very reliable except in extremely dusty environments  What is interesting here is that the tech-support person immediately  jumped to the solution.  That suggests that cables pulling on  an actuator is a well-known problem.

RE: re

Gentlemen,

I have explained in this forum several times, it is not cheapening at all, it is using the "stallguard" feature of new stepper motor drivers functionality identifying the home position without need of the end switches. 

As @joantabb explained, when you switch off the printer the actual position data is gone. Even they would be stored, nothing stops the user to move the haed and bed manually when printers is off. So when the printer starts, even the memorized potion can become useless. 

All the relative distances are measured by the stepper motors steps, therefore the printer needs an initial coordinates which is the  X,Y and Z home position. You can get this by homing - which you can see at the start of all prints, XYZ calibration, mesh bed leveling etc. ...

WHen you look at the last FW also stores the tests information on USB stick, which can be used for further diagnostics also for motor movements - using again the stallguard functionality for measuring the obstacles on the movement.

X-axis failing self test, help please!

I am having issues with my Prusa Mini+, I’ve had some issues recently with my prints shifting early on in prints (like when it’s still printing the skirt line) and doesn’t shit at all after, so I decided to selftest the printer and it’s failing on the x-axis check and won’t go any further.

I’ve asked a few Facebook groups, and everyone says “check the wiring”, I have no f***ing idea what that means. I took off the protector wrap around the wires - no visible damages, checked the board - nothing loose or disconnected.

Can anyone give me a link or something that will help me, Prusa’s message boards aren’t helpful, YouTube has absolutely no help, google is trash for answers.

greatpeople me kroger

same issue

I've been having this exact same issue, and the tests are all failing, telling me to check the wiring.  All wires seem to be connected and undamaged.   It's interesting to see the same problems showing up lately.   I'm going to try and spend some time doing some basic diag this weekend, starting with a factory reset and update the firmware if need be, then it'll be on to unhooking and reconnecting wires, lubricate the bearings, etc) and see if that helps.   I'll keep you all posted.

Problem solved for my specific case

Same problem:axis-x test fail. After testing a lot of things I notice that fail in the first right/left X move. This test is to verify that the x-motor is ok and is composed of 3 movements (each one faster than the previous). So I asume that the measure of X axis is wrong. And this is my problem:

* The x-axis is too long because the way that the engine drive belt was tensioned

* Mounting is too low tighten so... I use the two screws to tighten it. But this increase too much the X-axis distance for the self test

* Solution:  remove the extruder, tight it by hand, and remount it. Finally tight it a little with the screws.

Now all work perfect. Hope this helps!

Derrick

Darrick,

Can you provide the x axistest.txt file from usb stick?

Malabor

Did you succeed ať least with one print?

Does during test of the particular axis moving the correct axis (plugging the motor plug into an incorrect plug can lead to the issue that you are moving the incorrect motor- that's why the wiring question).

The other possible reason of failed axis test can be a bearing friction.

zoltan

yes, Up until these recent fails, I've been able to print no problem (aside from the occasional mishap, which is usually my fault for not setting up the files correctly.)

so, after removing a few pieces by the hotend fan, I noticed that there was a glob of filament stuck.  After removing that, and reassembling, I was able to get the printer to pass it's tests.   That's when it got weirder.   Now when I try to print, the machine fails the bedleveling test at the start of the print.   I can run a bed level test on it's own, and it's fine.   It's when I go to actually print something is when it fails.  Any suggestions on that one?

Malabor

Can you please describe in more details what exactly means "....it fails" - error message or mbl does not finish or ... ? Short video would be great.

fails

Posted by: @malabor

yes, Up until these recent fails.

Please define "fails".  

RE: Zoltan & cwbullet

I mean it fails the self leveling test performed before every print.  Whether it's a prusa test file (like the name plate in the video) or a custom .stl, it will fail if the print requires the whole bed.

I've attached a short video and some photos of the 'calibration print' square.

Set up

I do not see the the photos or video.  Did the self test calibration complete successfully in the wizard when you set the printer up?

video of "failure"

video...second try.

trying again to post the video,

photo of calibration tests

attempting to post the photo of the calibration test square.   
It really looks to me that the physical bed itself is off level on one side.   Is it possible that it's been bent?