MMU2 - Power loss story  

MMU2 - Power loss story

Hello,

I'm currently running a 34 hours MMU2 print and here is a story what happened today.
The print was started yesterday and was running through the night. At some point the FINDA sensor got dirty and the printer was in the waiting mode most of the night. I woke up in the morning and everything was dark, no light, no electricity. hm.... I looked at almost half through printed object and was already cleaning the sheet in my mind putting everything to trash.

But ... I updated yesterday my printer to the most recent versions and something with power loss recovery was there. So it was a great test for it. After waiting for two hours, the power came back. The printer booted up and a friendly greeting "Power loss detected. Resume print?" was laughing at me.
Well, of course I gave it a shot:
-> Printer started to warm up, but only the bed. Once bed was warmed up, nothing happened. My guess was it is waiting for the nozzle reaching it's temperature but it wasn't set. So I did it manually and after nozzle showed me my 205C, it started to resume the print.
-> BUT no filament was loaded and he was "printing" at the right spot but without filament. I paused the print immediately. MMU2 didn't want to load any filament, so I did it manually. Reset the MMU2, loaded the right filament by hand into the nozzle (display was showing which F-Position it needed). Printer was resumed and start printing again with filament and the right spot!
-> Great, I couldn't believe I can really safe this print. Well... one more surprise was waiting for me. After the first layer was printed and color change was due, the printer made his cooling moves, removed it from the extruder but instead of unloading it, the MMU2 moved to the next filament.
-> ARGH! Paused the printer again. Was able to remove the mess in the MMU2, made the printer load the right filament... and ....
-> Finally the next layer change was unloaded and loaded correct. Printer was printing again without any skipped layer!!!

You might think the story is over. Not yet! After one hour of happy printing, we lost again power. My APC UPS was depleted from the last power loss, so I just saw the error message "Recovering print". The bed moved to the rear position, nozzle to 0,0. MMU2 started to rattle and power was gone.... again ...

I thought what a horrible way to go into power-loss mode....
Believe it or not. The printer really offered me a recovery ....again.... I had to do all the manual stuff like described above ..... again.... But the most important part: IT'S PRINTING AGAIN

Once the print will finish, I will post a picture of it. You can see the power loss line and one of my mistakes but overall not too bad.

Thanks for reading ....