I have the K2 Plus with three CFS units. All had been working fine. On the last print the third slot of the 2nd CFS ejected a full spool at 90% completion, then threw the out of filament message. Attempts to re-insert and restart fail with a bogus clog message. A restart of the printer everything seems back to normal, but it does the same thing in the next print. Weird! Given the other two CFS units continue to work fine, I assume it is a hardware issue?
If the other to CFSs are working fine I think you may be into a CFS disassembly. Are slots 1,2 and 4 working on the suspect CFS? There was a user that had an issue with the really cool looking teetertotter reversing drive in the CFS where the main drive gear for one of the slots was slipping on the shaft and not driving. He crazy glued it back to the shaft (very very carefully) as a temporary fix and apparently was still working fine when a warranty drive arrived from Creality. What faults is it throwing?
I did open it up. Creatlity had sent me a replacement motor for a separate issue. I replaced it, though I didn’t think it was a hardware problem per se. No change. The weird thing is if I pull the cables, re-start the printer, everything looks fine. Each of the slots pull in the filament. I print the multi-color boat from the USB and it prints 99% (Black is in the third slot) and then it just decides to retrack the filament prior to finishing. It throws the filament out message and then the entire unit is non-responsive until I pull the power cable from the back and power on and off the printer. Another clue, if I just power it on and off without pull the cable first it doesn’t work. WEIRD!!! I thought it might be something in the G code, but any thing I print multi-color that hits that slot it does the same thing, 99% and then it just retracts. Also, If I put the filament in another CFS, it works fine.
Damn, you have a ghost in the machine!
Hard repower fixes it (until it uses slot 3), not the filament for sure.
Of the five motor and drive assemblies in the CFS, was the one you replaced underneath or the specific slot 3 motor and drive assembly with what looks to be a filament out sensor integrated into it? It is part of the assembly of 4 at the front of the CFS. If the slot 3 drive and sensor etc is new, it may be something to do with the CFS motherboard or wiring and connectors from the CFS motherboard to the front slot 3 drive. If it was the motor and drive underneath then I would pull the CFS apart and swap the front drives for slot 2 and 3 and see where the problem is after that. Even if it wasn’t I would still switch slot 2 and 3 drives to see where the problem goes. If still 3, MOBO and cabling. If it moves to 2, the slot drive.
How about the cable to that CFS, clutching at straws here as I believe it uses RS-485 communications, very unlikely though. Power everything off, swap cables about liberally and retry. Something to eliminate I suppose. I am assuming if you put a failed slot 3 filament in a different slot in the same CFS is works fine as you noted it did in other CFSs. Sorry about all the questions, old controls engineer here with over 35 years of debugging industrial radiation and Ex rated chemical control system. Beauty of the CFS is that if it goes AWOL you don’t die. I think we just need to load the parts cannon with the right ammunition, lol.
I have no idea what might be happening but just wanted to say the trouble shooting info provided on this forum seems first rate. I’m storing Cannonman’s replies for future reference.
Sudden filament ejection of a spool in a CFS slot may indicate a faulty photoelectric sensor PCB on the Hub outlet. See error FR2836 for more info.
If the blue indicator light(s) on the photoelectric sensor PCB are on when there is no filament in the Hub outlet then it will likely need replacement.
I had this happen to me, periodically at first after a few successful prints, then eventually total failure. Contacted support and they have agreed to send a replacement PCB.