Idler Shaft Clicking - No Movement
First of all, thank you to anyone helping me. I am greatly annoyed with my new Prusa MK3S+ ever since I started installing the MMU2 I purchased for it. Loved the thing until then. I want to love it again, even if it's taking this bloody thing off it and throwing it in the trash. <End rant here>
So, I thought I had put this thing together correctly. MK3S Extruder is working as it should. Loaded all 5 filaments into the MMU2. Tested it a few times by running Load, then Unload on all. I started my first multi-color print. First color from the position #1 loaded and printed my black. When it wanted to change, it attempted to load the #3 filament, but all I heard was clicking, and then the printer LCD showed me an error in the MMU. All MMU lights were blinking red, the puller was positioned to the left most area, and the idler pulley was clicking and not moving like it was stuck.
I powered off the printer. Upon turning it back on, the pulley doesn't move at all, all 5 lights flash red, and the pulley continues to click. I opened the hatch on the MMU to verify no filament was stuck anywhere I could see. When the unit is off, I can freely move the puller back and forth turning the long screw thingy. I have no clue what is happening. I have unmounted the MMU from the printer, and have it sitting on my desk, thinking I'm going to have to tear this thing down.
Anyone have any thoughts on this? I did adjust the tension of the idler body, attempting to loosen and tighten it. Neither way helped. Seems like the pulley shaft is just stuck. Are there recommended part upgrades that will solve all the MMU's problems? lol If so, can you link them in here.
(Forgive me if my terms of parts are wrong. I'm new, and frustrated! Wish they would have sent me an already build and tested unit. I would have paid for that.)
RE: Idler Shaft Clicking - No Movement
Are you 100% sure that its the MMU2s idler doing the clicking? I believe normally it will only do so when homing for a few seconds. If you have clicking noises from your extruder when loading filament, then check your bondtech gears on both sides of the filament, confirm they are properly mounted.
RE: Idler Shaft Clicking - No Movement
Sorry but what I gave in my previous post may have been bad info. I stumbled upon this article, you should check out the bottom video as it is a trouble shooting guide for precisely your problem:
RE: Idler Shaft Clicking - No Movement
Was the clicking from the extruder or the MMU? You said it unloaded #1 but didn't move from that position? If that's what the 'clicking' noise was then it'll probably mean the filament wasn't pulled back enough, and that was jamming the selector moving from #1 to #3. But you say you can move the selector back and forth when it's powered down. So it can't be that. Did you notice if the FINDA probe changed state? (Or the ball bearing dropped down as the filament was pulled back?) It could be the case the it didn't retract enough, and if that happened the selector wouldn't move. With the stepper motors being energised you'd not be able to move them manually.
Another thought would be that there was filament strings blocking the ball bearing from dropping when the filament retracted. But if this were your first attempt with the MMU then that's hardly likely. There's a mod' for the selector that adds a magnet to help pull the ball bearing down, and also gives better access to that area to clear out filament strings that could cause a problem. I can't vouch for it, but it's something that I've been meaning to try; https://www.prusaprinters.org/prints/25169-mmu2s-r2-selector-finda-remix-with-magnet
Have a search around though - there's a few modifications to this part that people have made.
There's also some major improvements people have designed to ease the filament path into the MMU; friction is really not a good thing and anything you can do to make the filament glide into the MMU more smoothly will seriously help. I summarised the wisdom of this group in a reply to this post; https://forum.prusa3d.com/forum/original-prusa-i3-mmu2s-mmu2-assembly-and-first-prints-troubleshooting/first-layer-calibration-mmu2s-constantly-loads-and-unloads-the-filament-to-the-nozzle/ Print the MMU back end part, the bit that grips the PTFE tubes at the buffer facing end. That alone cured all my problems. It occurs that the 'clicking' noise may have been filament being ground up by the gears because they couldn't push it backwards.
Hope that helps.
RE: Idler Shaft Clicking - No Movement
Sorry for the delayed response. I've been away camping with the kids. The noise is not the extruder. It's definately the MMU. I printed new parts, and will disassemble the MMU to try a few of the tips above. Will respond this week with an update.