MMU3 firmware on MMU2s fails - rattling selector  

RE: MMU3 firmware on MMU2s fails - rattling selector

Did you select mmu on in lcd menu it's auto turned off on update

RE: MMU3 firmware on MMU2s fails - rattling selector

I just did, however the situation is like I am stuck, MMU2s rattling, and message on printer is "IDLER CANNOT HOME" I can only retry the test, I totally freed idler (unmount from selector), tested if it can rotate freely from one side to another, everything looks ok, it can move and stop at stoppoints. However the printer after retrying rattles the idler and ended again with that error message.

Prusa must hate me for some reason :-/

RE: MMU3 firmware on MMU2s fails - rattling selector

I had the same issue. See: https://github.com/prusa3d/Prusa-Firmware/issues/4285

Enable the MMU and then send "M708 A0x19 X5" to the printer to decrease the idler sensitivity.

RE: MMU3 firmware on MMU2s fails - rattling selector

I found that if I follow that procedure I can sometimes get it to work, but only if I ALSO completely open the idler tension... rendering the thing basically useless.

Why does it now go through the 3 long duration rattling steps, anyway? This wasn't required before to get into a ready state. 

Has anyone heard of there is an update coming to fix this?  I don't want to have to putty into my printer every time I start the thing... that seems like something 2012 me would have had to do because there was no choice; not 2023 me.  

RE: MMU3 firmware on MMU2s fails - rattling selector

Hello,

how can I send a G code to the printer ?

Do not have raspery only USB connection.Thanks a lot !

RE: MMU3 firmware on MMU2s fails - rattling selector

Just for information, I updated MK3S+ incl. MMU2s to FW 3.13.1 incl. MMU 3.0 (printer first after that MMU - starting from 3.10.1/1.06 - with MMU setting "ON" like required). The FW updates ended sucessfully.

I got similar problems the idler rattles (but then moves) and the selector makes horrible noise (turning very fast forward and back). The MMU then tries to load/unload the filament (status unloaded but feeder turns in unload direction and did not really move any filament) and says that FINDA could not recognize filament (never seen such message in the display - all prevoius failures I had with MMU were just indicated by the LED's not the printer display?).

After several tries (and a short look into this forum) I downgraded the FW to 3.12.2 incl. MMU 1.06 (MMU first then printer).

Now it works fine again.

I wonder that Prusa does not warn MMU users, if I take a look to the results of the poll started in the forum?

RE: MMU3 firmware on MMU2s fails - rattling selector

Same issue, downgrading both MMU and Printer. For some reason the printer also lost all its calibration after upgrading, requiring me to go through the entire calibration. Also lost my z offset. grrrr.

RE: MMU3 firmware on MMU2s fails - rattling selector

I don't think the MMU2s suppors MMU3 firmware. Did this happen before you upgraded?

RE: MMU3 firmware on MMU2s fails - rattling selector

Hi,

This is from readme.txt with newest firmware release:

Compatibility of the printers with MMU2S unit running MMU3 firmware

- Original Prusa MK3S - compatible, firmware file included

- Original Prusa MK2.5S - under investigation, files not included for now

RE: MMU3 firmware on MMU2s fails - rattling selector

I have three PRUSA MK3S+ printers and it happened to all of them after I came back from vacation last December, that is after upgrading the firmware to MMU3. Same sound, same error. I troubleshooted with PRUSA and I did not find any mechanical issues. Checked all the connections and played it with little bit, resetted the MMU2Ss, and reflashed with MMU3 firmware, they all started working the following day except one. That printer constantly gives me the error message, prusa.io/04125. When this error appeared, I was in the middle of an important print. I realized when it happened, turning off the printer and turning it back on would continue printing. The printer will ask, "Blackout occur, continue printing?" every time when I turn it off after the error message and turned back on several times. In that way, I could save the print (I know.. it's a pain...you have to keep your eyes open everytime, I have remote cameras set to my printers, so easy to monitor). however, that problem is still there in one of the printers. It is a bug, there are no mechanical issues with my MMU2Ss.

RE: MMU3 firmware on MMU2s fails - rattling selector

If I understand correctly, the MMU Malfunctions, and you have found that causing a power panic scenario, allows you to restart the printer and reset the MMU in the process? 

there have been many theories about MMU2's and errors. 

One prevailing theory is that there are electronic power issues between the Einsy and the MMU Controller.  
the original Power for the controller logic, was, I believe, derived from the Data cable, whilst the power for the motors was derived from the 24 volt power supply....   All of these connections went through Plug and Socket connectors on the edge of the MMU2 controller board...   and I understand the net result was, that the 5 volt logic power supply was poor and unreliable, on some printers... 
Now I have never knowingly had this problem myself.... 
AND, Now I have the revised Power board for the MMU3... 
which provides the new little local power source.  (derived from 24 volts)

However, putting that aside. 

The MMU3 set up, still feeds power through the plugs and sockets on the edge of the MMU controller board. there is no cutting tracks or shorting diodes or similar. 

so many of the home grown remedies which involve circuit modification, may be over complicated or risky... 

Looking from outside the problem, inwards... 

I would suggest that you remove the mains power plug, from the wall,  pop the top cover off the MMU Controller, (Which will take the Controller board with it), turn the board over, so that you can see the plugs and sockets and uplug / re plug the power connector and the data connector four or five times to try and ensure that there are no oxides on the connector pins, then I would get a dab of Vaseline (Petroleum Jelly) and smear it on the ends of the connectors, before re connecting  the connectors, to give them the best chance of success. 
Then, try the printer again. If you still have power issues, consider leaving your USB Cable plugged into the programming port on your MMU, and a powered USB'A' connector    say a 5 volt phone charger... to effectively provide a local 5 volt supply... 

and you may well find that your issues go away. 

Prusa's MMU3 electronics  upgrades involve a new daughter board which clips onto the power and data connectors on the mmu2 controller board, and new wires to connect to the Einsy data connector and the 24 volt PSU connections, since this seems to work, it is unlikely that any circuit changes within the MMU Controller, are necessary. 

regards Joan

RE: MMU3 firmware on MMU2s fails - rattling selector

Thanks for the reply.

It doesn't come to a power panic scenario, but I turned it off to save my print. Ok. here is what happened. As I said... one printer constantly gave me trouble with the "prusa.io/04125" or "selector cannot home" error. When I started to print it was all going well and 1 hour later, the printer stopped and started beeping with the above error code on the panel. I wanted to save the print because only 1 hour left to finish it, so instead of 'retry' and changing the sensitivity (I have done this before, but it didn't help), I turned the printer off and turned it back on to see if it solved the issue. Vola! error is gone and in the panel it says. "Blackout occurs, continue printing Yes/No". I pressed yes and the printer started to print for another 15 minutes and started to give the same error while beeping. I turned it off and turned it back on again, the error is gone and in the display it says. "Blackout occurs, continue printing" Yes/No...etc...etc. and continue this until the print, (yes, I know it's dumb...) and was able to save the print.  I am now going to try cleaning all the connectors, like you said to see if that makes any difference. I am pretty sure it will be fixed itself since my other two printers are working fine right now. 

RE: MMU3 firmware on MMU2s fails - rattling selector

the comment

"Blackout occurs, continue printing Yes/No".

suggests that turning the power off, caused the printer to save the current position information and prompt for a restart. 
That sounds like the firmware process for restoring from a power failure, which is the 'power panic' process... 

anyway, not a lot of point debating that point... 
If cleaning the contacts clears the  problem, you won't care any more... 

Just a thought. you would be advised to clean the contacts at the other end of the MMU  Data wire, as well... 

regards joan

RE: MMU3 firmware on MMU2s fails - rattling selector

@martind Did you ever get a solution to this? I have also tried putting MMU3 firmware (3.0.3) on a board from the original MMU2, and I get the same bizarre light sequence shown in your video on startup. The idler and selector both home, and the buttons work to move the selector. However, the printer does not get any communication from the MMU. I have also tried erasing the EEPROM, just to be safe.