MMU2S keeps resetting/Red & Green LED's flashing at once.  

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Andarne
(@andarne)
Active Member

My MMU2S is behaving very erraticaly.

When I go to start a print from OctoPrint, the Mk3S will home and level the extruder. The MMU2S will then run through its startup sequence; the drum will rotate and bang against itself to home, the selector will home and then it'll move to whatever filament I've specified.

This is where the issue happens. The MMU2S will make a click, the drum will rotate ever so slightly, and all 5 LEDs will flash red/green three or four times. The MMU2S will then reset itself, do the exact same thing, for 2 more tries before it stays static with all the LEDs flashing red/green.

I have double-checked all the power connections inside the MMU2S board, and inside the board on the MK3S. I have also double-checked the tension screws on the MMU2S to make sure they're not too tight.

Sometimes, the issue will happen during a print when I go to change filament. Resulting in a failed print...

I'm using the latest firmware for the MK3S and MMU2S, and have re-flashed several times.

This topic was modified 2 months ago by Andarne
Posted : 13/08/2019 10:13 am
jorge.s4
(@jorge-s4)
Active Member

Did this recently start to happen? I was advised to re-seat all the data connections and the power connectors, both on the Einsy/Rambo board and on the MMU2s.  I also tried the newer Firmware the 1.0.6 and that solved my problem. Also check that the spring tension on the selector drum is not too tight i.e. the head of the screws are flush with the top of the part.

...
Posted : 17/08/2019 8:01 pm
roland.f3
(@roland-f3)
Active Member

Now I have this failure, on top of many others, also.
My solution was to was to remove the complete MMU and never install it again!
--> problem solved the printer is printing, with out any issues.

Soory about the sacasm, but the MMU is giving me trouble since I, unforunately, bought it a year ago.

Posted : 24/08/2019 8:43 pm
Andarne
(@andarne)
Active Member

So, update, I'm on the absolute latest firmware and it's still happening - always at the beginning of a print job, and often during a multi-material print. I have to turn the printer off at the mains for me to get a print going now.

Posted : 23/09/2019 11:58 am
vintagepc
(@vintagepc)
Noble Member

This is the MMU equivalent of a "crash detected". You have to reset the MMU with the reset button beside its USB connector.  (This LED code is in the handbook troubleshooting section)

It's been getting worse and worse for me as well; currently working with support to find the cause. 

Posted : 23/09/2019 12:19 pm
allen.m2
(@allen-m2)
Estimable Member

Having the same issue as well.  All connections to the MMU seem to be good.

Posted : 23/09/2019 4:32 pm
daevans315
(@daevans315)
Active Member

Just following the thread.    I'm seeing my MMU2 start to have this issue more and more.   I just re-seated both ends of all the connections and it didn't do it on the very first load but started again after a few dozen loads.

I3 MK3 MMU 2.0....
Posted : 25/09/2019 5:00 pm
vintagepc
(@vintagepc)
Noble Member

In the interest of finding a cause or at least a lead, could folks with this issue answer the following questions:

-> What PSU do you have? (silver stock/black stock/other you bought yourself(e.g. meanwell))

-> What MMU firmware version?

-> MMU in stealth or normal mode?

-> What does Support->Voltages report on your printer when this happens? If you have a DMM, also check/report voltages at the MMU board itself.

-> Do you have any non-stock mods to the MMU setup? (different spool holders, buffer changes, different PTFE...)

-> Where are your spools mounted? (above/below/behind printer)

 

 

Posted : 25/09/2019 5:10 pm
jmone
(@jmone)
Estimable Member

Mine has started doing something similar doing a MMU2s print, where you hear the MMU2s do a "resart" (it does the multi bang thing) and the Mk3s says there is a MMU2s Issue.  I then press the centre / right button on the MMU2s and it continues just fine..... (well till the next time).  Unfortunately, I've not seen the issue, only heard it and by then it is in the failed state.   I have plenty of mods but nothing that (I think) coincides with this change of behaviour.

- Meanwell PSU

- MMU V when it happen (I don't know as a resume the print).

- MMU in Stealth Mode

- Print from a 5 spool Dehydrator, use the Prusa PTFE but with Connectors to the back of the MMu2s

- Left and the Bottom Right steppers get pretty hot to the touch 

This post was modified 1 week ago by jmone
Posted : 07/10/2019 5:48 am
jmone
(@jmone)
Estimable Member

Firmware is 3.8.0 and 1.0.6-372

Voltage is 24.0 for Power and flicks between 24.0 and 24.1 for bed during the print

Posted : 07/10/2019 5:57 am
ironjoe13
(@ironjoe13)
Estimable Member

I have had this problem for a few months, and my solution was to lower the current of the MMU idler motor, haven't had any issues since.

#define CURRENT_RUNNING_STEALTH {35, 35, 38} // {35, 35, 45} // {?,?,910 mA}
#define CURRENT_RUNNING_NORMAL {30, 35, 40} // {30, 35, 47} // {?,?,910 mA}

Anything can be made better
https://www.myminifactory.com/users/ironjoe13...
Posted : 07/10/2019 5:01 pm
nikolai.r
(@nikolai-r)
Noble Member

I had also some weird behavior with MMU in stealth mode. Switched to normal mode and since then no issues anymore. 

Posted : 07/10/2019 7:23 pm
vintagepc
(@vintagepc)
Noble Member

Not conclusive yet but a board swap did not help; it was still having the reset problem.

*BUT* I noticed when working on it that when my hands were near or disturbing the power/data cables, I'd get weird behaviour in that other LEDs on the MMU would flicker faintly or light. I replaced the data and power leads and that no longer happens. I also have not had the reset  problem despite two MMU prints over the weekend (but only about 60-70 toolchanges total. I was printing PLA parts with PETG supports)

Inspection of the cables did not reveal anything unusual; continuity appeared fine and no high-resistance connections.

 

Posted : 07/10/2019 8:36 pm
Andarne
(@andarne)
Active Member
Posted by: @vintagepc

In the interest of finding a cause or at least a lead, could folks with this issue answer the following questions:

-> What PSU do you have? (silver stock/black stock/other you bought yourself(e.g. meanwell))

-> What MMU firmware version?

-> MMU in stealth or normal mode?

-> What does Support->Voltages report on your printer when this happens? If you have a DMM, also check/report voltages at the MMU board itself.

-> Do you have any non-stock mods to the MMU setup? (different spool holders, buffer changes, different PTFE...)

-> Where are your spools mounted? (above/below/behind printer)

 

 

PSU: Silver stock one from my Mk3

Latest firmware version

MMU is in stealth mode

Voltages: PWR - 23.7V, Bed - 23.9v

Using different spool holders, located beneath the printer, but been using them since building the printer.

Posted : 10/10/2019 1:42 pm
andre.l9
(@andre-l9)
Trusted Member
Posted by: @vintagepc

In the interest of finding a cause or at least a lead, could folks with this issue answer the following questions:

-> What PSU do you have? (silver stock/black stock/other you bought yourself(e.g. meanwell))

-> What MMU firmware version?

-> MMU in stealth or normal mode?

-> What does Support->Voltages report on your printer when this happens? If you have a DMM, also check/report voltages at the MMU board itself.

-> Do you have any non-stock mods to the MMU setup? (different spool holders, buffer changes, different PTFE...)

-> Where are your spools mounted? (above/below/behind printer)

 

 

PSU: Silver stock one from my Mk3

3.8.0 / 1.0.6

MMU is in normal mode

Voltages: PWR - 23.8V, Bed - 23.8v

Self made spool holders, located above the printer, no buffer, no rewind system, works well.

Just for information, I printed a lot of MM things with the Zero Beast firmware, never had this issue, only with stock firmware.

Posted : 10/10/2019 6:53 pm
nikolai.r
(@nikolai-r)
Noble Member
Posted by: @andre-l9
Just for information, I printed a lot of MM things with the Zero Beast firmware, never had this issue, only with stock firmware.

Just of curiosity. Why have you switched to stock firmware if you had no issues with ZeroBeast FW?

Posted : 10/10/2019 6:56 pm
andre.l9
(@andre-l9)
Trusted Member

@nikolai-r

I used the zero beast firmware before Prusa switched to the IR sensor, the zero beast was better and with a full fonctional filament sensor.

Since the MK3S upgrade I use stock firmware.

Posted : 10/10/2019 7:03 pm
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