MMU2S not loading to the nozzle
I have bene using my MMU2s on my MK3s in single mode for a while and its been ok. I went to do a multi colour print, loaded all 4 filaments in the MMU fine, started to print from SD card and at the start of the print it goes to load fillament 1 (expected) but as soon as the fillament triggeres the FINDA probe the mmu2 drive gear dissengages (with a green LED light), the extruder is waiting for the filament but it isnt driven down the tube to the extruder causing the print to time out with MMU2 error. I havent had this issue before so I am a bit lost.
I printed in single mode last night without a problem, it appears to be in multi mode. The firmware was up to date but ive just reflashed it just in case but still the same issue.
RE: MMU2S not loading to the nozzle
Your IR sensor/tower is not set correctly. It's probably stuck on 1 causing it to think filament has reached the extruder as soon as the FINDA detects it.
RE: MMU2S not loading to the nozzle
@vintagepc
I have verified the operation of the sensors and they are fine, they operate as expected. Its on 0 until filament touches the extruder gears then goes to 1. (I will tripple check later when i get home)
If it was an IR sensor problem, wouldnt the single mode loading fail too?
RE: MMU2S not loading to the nozzle
Weird. 95% of the time the sensors are the cause. You must be in the 5% 🙂 The sensor setup is a little weird in that some sensors are ignored at certain times and not at others - so you can't assume they always behave the same. (for example, there's a bug where if your FINDA reads 0 and the IR reads 1 at print start, your printer will reboot instead of starting the print)
Sorry if you've already done this, but have you also checked the FINDA to make sure it is also behaving as expected and rock solid? I recently had something similar with my system and it was because one of the sensors was flickering from vibrations and being at the edge of the changeover. It was solid when idle but with the extuder turning there was just enough movement to cause it to trip. The LCD update rate isn't as fast as you might think, so it could be flipping but not showing.
My next step would be connecting to the printer with pronterface (or any serial terminal of your preference) and starting your print - watch, and copy and paste the log from the serial output terminal. That may provide some insight as to what is going on.
RE: MMU2S not loading to the nozzle
@vintagepc
oh for pete sake. I think your 95% statistic is right.
Wasnt getting a good output on ponterface so I decided to tripple check the sensors, they were working. didnt trust it and dissasembled the IR sensor and found a small bit of black fillament sraping right next to the sensor (didnt see it due to it being the same colour). that must have been vibrating and interrupted the IR sensor when loading. Removed it and now it loads during the print.
By the looks of it (and what you said) it doesnt check the sensor when loading on single mode otherwise it would have had the same problem.
Thank you for your time and patience while I figured this out.