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leopold.s2
(@leopold-s2)
New Member
MMU2S Loading problem

Hi there,

I just finished the assembly of my MMU2S unit and now I am completely stuck with the chapter 7.3 "First Layer Calibration" in the "MMU2 Printing Handbook".
The issue it, that there is no filament leaving the MMU unit beyond the FINDA-sensor.

Steps I perform:

  • I let all 5 filaments load with LCD-menu -> load filament -> load all.
  • the selector takes the filament and loads according written in chapter 6.1 before moving to the next filament. The loading procedure ends successfully (at least according the LCD).
  • I can see the end of the filament when I look into the small PTFE tubes.
  • However, when I start the First-Layer Calibration from the LCD (e.g. for Filament 4) no filament is sent beyond the FINDA-sensor.
  • The following happens:
  1. I perform "Load all"
  2. I start "First Layer Calibration", then the bed and the nozzle is heated up
  3. this is then followed by controlling the z-height at the well-known 9 positions on the bed
  4. Then the MMU-selector moves to first filemant (since I have chosen filamtent 1)
  5. MMU does something and the LED for filament 1 switches between green and red, but no filament is visible in the PTFE beyond the FINDA
  6. LCD says "MMU load failed", but filement LED on the MMU is green!
  7. Sensor info says 0 for all three sensors.
  8. I need to reset the printer with the X-button near the LCD as I cannot cancel the first-layer-calibration procedure otherwise.
  • I checked the FINDA-sensor for proper operation pushing some filement from the rear side and noticed the Support/Sensor-Info/FINDA-value going from 0 to 1. So this seems to be ok.

Main Firmware: 3.8.1-2869
MMU Firmware: 1.0.6-372.

Any help appreciated, as I am completely stuck and cannot even print with one color.

One strange thing I noticed:

I spent many hours today and I noticed twice a strange behaviour: When I told him to load filament 1 actually the filament 5 was loaded into the air (since the selector was at filament 1 and the shart PFTE-tube for filemament 5 was open). But this happend only twice...

 

Best regards

Leo

Posted : 09/02/2020 7:48 pm
rebelgnome
(@rebelgnome)
Active Member
RE: MMU2S Loading problem

Hey Leo,

Just been playing with this myself. 

First, you said there was a zero reading on all 3 sensors... Part 7.1 of the book shows how to calibrate this and it's really important as it doesn't work otherwise but I don't think it's needed for the feed from the unit to the extruder.

I managed to get the first four filament loaded to the extruder by going to the "Load to Nozzle" item in the LCD menu... apart from that I'm still trying to get it working on the 5th filament loader.

Posted : 08/03/2020 5:54 am
charles.r12
(@charles-r12)
New Member
RE: MMU2S Loading problem

Hi all,

I'm also experiencing the same issue after performing the upgrade from MK3 MMU2 to MK3S MMU2S this weekend. The printer was performing fine before.  At first, I had the IR calibration issue, the first layer calibration would end up in a blob being generated, but at least the filament was leaving the MMU2S. For some reason, it now refuses to load filament up to the extruder.

@Leo, I second matt, please check your calibration. And just in case, ensure you've used the proper IR cable, the kit includes one MK2.5S and one MK3S cable (You'd want the black-red-white wire one for the MK3S).

Cheers guys,

Charles

 

Posted : 30/03/2020 1:20 pm
brian.h31
(@brian-h31)
New Member
RE: MMU2S Loading problem

Hi all,

I see this is an old post so hopefully you have solved your issues by now, but I noticed you said it went to red-green flashing. This is good and means everything is ready to resume you just have to press the right-button in the cluster of 3 on the MMU

If the red light is flashing slowly or quickly it means there was an issue loading or unloading. Clicking the center button will retry the load/unload. Once the unit confirms the issue is resolved the lights start flashing red-green and you need to click the right button to resume.

Hope this helps someone,

Brian

Posted : 01/04/2020 1:12 pm
wgoossen09
(@wgoossen09)
New Member
RE: MMU2S Loading problem

I have the very same issues with the MMU not loading the filament as it seems to rotate the motor but can not grab the filament to send it through even despite my adjusting the spring tension or not.  Yet, I can push the filament into the unit through the clear tub and down to the extruder without much resistance though it does seem to catch occasionally at the FINDA sensor area.  This is when I tell it to load to the nozzel.  It tells me that the MMU needs user attention eventually after a few minutes trying to load and then it appears to try and unload also failing at this.

Posted : 05/04/2020 3:06 pm
dominik.s11
(@dominik-s11)
New Member
RE: MMU2S Loading problem

I have the very same problem, right after upgrading from MK3/MMU2 to the S versions. Firmware is 3.8.1 / 1.0.6.

Filament load works, but when it should load to the nozzle, filament is pulled in only up to probably the FINDA. Instead of then beeing pushed fast forward to the extruder, the extruder gears move, but not the filament. A few seconds later it is retracted from the selector.

When trying to push it manually to the extruder, this can be done without too big resistance, so I'm sure, the filament path is clear. However, you can not do this fast enough before the load operation times out and retracts...

FINDA and IR sensors work as expected when checking in the menus Support | Sensors section and inserting/removing filament at the selector and extruder gears.

Filament loading works fine in the single mode for printing. Prints perfectly than. So I feel this to be a software error instead of a mechanical problem.

Any ideas?

Thanks a lot

Dominik

Posted : 29/04/2020 4:43 pm
NarlyB
(@narlyb)
Active Member
RE: MMU2S Loading problem

@dominik-s11

I experienced this same issue.  I worked with support.

The fix they gave me worked and really caught me off guard.

The tech told me to adjust the two spring loaded screws on the mmu2 cover to 1.5mm below the top surface.

I always have those just below but not that much.

I was skeptical but tried anyways

It worked flawlessly after I adjusted the screws.

Posted : 30/05/2020 9:01 pm
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