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MikiCab
(@mikicab)
Estimable Member
MMUs intermittently not being seen by the printer

My MMU is intermittently not being seen by the printer.  I have had the MMUs since it launched and this is a new issue.  Has anyone else seen this.  I am thinking it maybe reseating the cables?

Posted : 13/03/2021 5:39 pm
Diem
 Diem
(@diem)
Noble Member
RE: MMUs intermittently not being seen by the printer

Yes, pull and reinsert all of them.  If that fails there is an outside chance a cable has broken - test continuity with a multimeter.

Cheerio,

Posted : 13/03/2021 8:15 pm
EJTH
 EJTH
(@ejth)
Eminent Member
RE: MMUs intermittently not being seen by the printer

What do you mean by intermiddently not seen by the printer? Like is it not detected at all, or is it giving you cryptic messages telling you to manually change filament during multi material prints?

Posted : 18/03/2021 3:49 pm
GG0034
(@gg0034)
Active Member
RE: MMUs intermittently not being seen by the printer

hello, I allow myself to interfere in your post so as not to create another on the same subject. I happen to have this problem with a message received during a multimaterial printing where you have to change the filament manually with the "Beeps" that go with it. this happened to me on two long print attempts (several hours each time (> 28h)) and in both cases at the same time but not at the same time of printing (with the same file) maybe a coincidence. despite the change of filament made, the printing failed because of an offset of the plate following the hooking of the nozzle on the purge tower. that's it for the details. my printer is an i3 MK2.5s with MMu2s optimized with 2.5 ID PTFE tubes and some fine adjustments. for shorter prints (smaller objects) everything is generally fine. even in five colors. at this point I don't know where to look for the cause. I tried printing from SD card and also via Octoprint but the problem happened with both modes.

Posted : 19/03/2021 1:53 pm
MikiCab
(@mikicab)
Estimable Member
Topic starter answered:
RE: MMUs intermittently not being seen by the printer
Posted by: @ejth

What do you mean by intermiddently not seen by the printer? Like is it not detected at all, or is it giving you cryptic messages telling you to manually change filament during multi material prints?

It tells me to manually change the filament in the middle of a print.  I don't think it is a broken wire since these wires do not flex.  I have been and Field Engineer for over 30 years and what I am suspecting is DC connections can become intermittent because the current only goes in one direction and causing a transfer of material from one connector to the other which can give you intermittent connection.  Every engineer from 30 years ago always carried an eraser with them to clean connectors.   Once I get some extra time I will pop the connections and give them a good cleaning with an eraser.

Posted : 19/03/2021 2:02 pm
EJTH
 EJTH
(@ejth)
Eminent Member
RE: MMUs intermittently not being seen by the printer

I asked because I recently encountered the same issue when switching to a different filament. The problem is MOST likely related to the IR sensor on the extruder. I suggest calibrating it (by loosening it and moving it a little bit towards the right, then make sure its secured).

 

https://help.prusa3d.com/en/article/ir-filament-sensor-calibration-mmu2s_2245/

 

If that doesn't work. Try doing a factory reset too!

https://help.prusa3d.com/en/article/factory-reset-mmu2s_1920/

I say this because this seemed to work when I had the problem after realigning the FINDA... But it makes more sense that its actually the IR sensor out of alignment.

Remember to use the allen key when aligning the sensor initially, this allows for some tolerance in accepted filament.

This post was modified 6 months ago 4 times by EJTH
Posted : 19/03/2021 2:16 pm
EJTH
 EJTH
(@ejth)
Eminent Member
RE: MMUs intermittently not being seen by the printer

Let me know if it helped!

Have a good weekend, I hope your MMU wants to play nice!

Posted : 19/03/2021 2:36 pm
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