Minimal rolling back from MK3S-MMU2S to MK3S
Hello,
I upgraded my MK3S to MMU2S a few months ago and it's been a headache. I'd like to restore the printer to MK3S in the least time/effort possible since I'm a bit pressed on time. Any advice?
Thanks,
Othman
Best Answer by Kevin Hughes:
After weeks of frustration and months of not using my printer, I decided to go back to what works.
Steps I took to disable/remove MMU temporarily:
1. Uplug power and data connectors on MMU board. These are the 2 connectors on the right.
2. Disconnected PTFE tube from extruder at the blue collar. I put in a short PTFE tube I had laying around.
3. Removed MMU assembly from the top frame and set it behind the printer. The wiring is still connected. Re-installed the original spool holder to the top of the frame.
That is all. Printer says it is a MK3S and operates as it should.
This also allowed me to verify the MMU2 was the source of my problems as the MK3S still works flawlessly.
The MMU is still wired in and easy to reconnect if I want more pain and frustration later.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
It doesn't take long at all to roll it right back, I've done so once or twice, as I rarely use the MMU2S, and prefer to use it stock when doing lots of bulk runs (but that's another story).
You just need to swap out the 'chimney' on the extruder, leave the sensor as it is (don't bother to readjust the length of the cable, just ensure it won't catch on anything), swap the door over, and undo a couple of bolts to refit the piece with the ball bearing in. Undo the control box, remove the FINDA sensor cable, and the power cables (the power cables are probably the fiddliest part). All in, around 40 mins or so at a conservative pace.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
@apromain
I’ve considered rolling back as well. I’ve thought the process over several times, and I don’t really see a need to remove the chimney, and put the ball bearing back in. Seems to me leaving the sensor in the chimney without the ball bearing would work just as well.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
I've taken a lazy approach to this a few times when I can't be bothered to change the filament loaded in the buffer and MMU2S, but just want to run a single-colour print.
I have a short piece of bowden tube to hand; disconnect the MMU2S bowden tube from the hot end (just press down on the pneumatic fitting and pull the tube out), stick the short piece in instead, and disconnect the data cable from the MMU2S itself (with the printer off, of course). Takes a couple of minutes, if that. I'm tempted to fit an in-line switch on the data cable to make that last part instant...
Takes a little encouragement to get the filament to autoload (need to push it into the hob gears) but I've not had any difficulty doing that once I twigged that's what it takes to get the hot end filament sensor to trip. Slice with the normal MK3S printer profile of course, as the MMU2S is then not being used at all.
Also I don't know if over time this will wear the pneumatic fitting, but that's hardly an expensive component to replace 😀
RE: Minimal rolling back from MK3S-MMU2S to MK3S
I kept the chimney in place, unscrewed the QSM-M5 connector from the extruder, turned off the filament sensors, and then loaded manually. Pre-heating and then moving the extruder axis until it loaded.
It wasn't perfect but it worked for me!
RE: Minimal rolling back from MK3S-MMU2S to MK3S
After spending a few months trying to print unsuccessfully, I happened upon your post and immediately printed my first object in months.
Apparently you can just unplug the mmu2s, disconnect the PTFE tube and be back to printing perfectly. Who knew?
Thanks for this post, you're a godsend! This should be stickied.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
After weeks of frustration and months of not using my printer, I decided to go back to what works.
Steps I took to disable/remove MMU temporarily:
1. Uplug power and data connectors on MMU board. These are the 2 connectors on the right.
2. Disconnected PTFE tube from extruder at the blue collar. I put in a short PTFE tube I had laying around.
3. Removed MMU assembly from the top frame and set it behind the printer. The wiring is still connected. Re-installed the original spool holder to the top of the frame.
That is all. Printer says it is a MK3S and operates as it should.
This also allowed me to verify the MMU2 was the source of my problems as the MK3S still works flawlessly.
The MMU is still wired in and easy to reconnect if I want more pain and frustration later.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
Thanks, Kevin! This has worked. It only took 5 minutes to do.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
Just want to point out that you don't actually have to disconnect power to the MMU2S, you can just unplug the data connectors.
Obviously there are pros and cons, but if you want to do less work to change back and forth, power disconnection is not necessary.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
I tried this, but I'm having trouble with the filament sensor in the chimney. When I got the MMU2S, it came with the MK3 -> MK3S upgrade as well, so I don't have the lever/magnets that are in the current instructions. Does anyone have a complete list of parts I need to order & print to get back to a "standard" MK3S ?
RE: Minimal rolling back from MK3S-MMU2S to MK3S
Plus, extruder top, filament sensor, Bondtech door , and filament sensor ball adapter
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Minimal rolling back from MK3S-MMU2S to MK3S
you end up with a spare cable and spare sensor... with the above parts
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Minimal rolling back from MK3S-MMU2S to MK3S
Hi,
pls help me to understand ... I just received my delivery of the MMU2S kit. ( YES, i did it. Let us see if I experience the same pain like others .. or not).
As I do not want to assemble all-at-once ( enclosure modification required etc etc ) , please tell me, if I understood the above in the thread correct supporting what i also took away from reading the assembly instructions:
I can use the "3B. MK3S/MK2.5S extruder upgrade" ( assembly instructions) without the MMU in place and "simply" have an upgraded extruder on my I3 MK3S with a small PTFE tube, correct???
Thanks everyody for helping me.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
Yes you can. There are others here that added a switch to power of the mmu and use the mk3 as normal.
Only thing that I see that would work differently is loading the filament as the sensor is now triggered by moving the bondtech gears.
I just installed the mmu myself and couldn't push the filament in by hand and trigger the sensor. I thing the gears have to turn. That should work with the lcd I guess.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
@Baklin
thank you for your reply already indicates the directiin to me.
Do not take me wrong, but I read some uncertainties and assumptions which i would like to avoid to experience.
Can anybody else helpe me with some clear advices including the pitfalls / shortcommings that @Baklin pointed to?
i would like to achive as much continuity in usage as possible - not many hours /daysof no printing - and therefore want to stage the approach without tooo much additional trouble.
Advices much appreciated.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
No problem. I understand your problem and want you want. It is a waste of time if you can't print after part of the upgrade and don't have time to do the full upgrade to get it working again.
I have installed my MMU a few days ago. At the moment it is printing. But when it finishes in a few hours I will see how it works if I bypass the MMU and use the MK3s as an single material machine using the upgraded extruder.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
@baklin
thx, cool. I would NOT be surprised with MMU switched off, the new Filament Sensor would work normal ... depending on the guys did design the firmware that way.... means .. I hope it is that way 😉
RE: Minimal rolling back from MK3S-MMU2S to MK3S
Still printing.
The new location for the of the filament sensor compared to the normal MK3s makes it useless, I think.
The sensor is now triggered when the filament is between the bondtech gears. Not above the gears like before.
So when the filament runs out is it only detected when the gears push the last piece from between the gears. Now it will trigger a filament runout but can't pull the last piece out again as it is already past the gears. With the MMU the filament run out is sensed by the sensor in the MMU.
That way the gears in the extruder can pull the filament back and hand it over the the MMU to unload it.
Without the MMU, but with the upgraded extruder you will have to make sure you won't runout of filament.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
Print finished.
I can load the filament after disabling "autoload filament" in "settings" Without that disabled the printer waits for the filament sensor to trigger, but you can as you can't push the filament between the gears. (I didn't disable the filament sensor, just the autoload)
With autoload disabled the gears start spinning as soon as you click load filament on the lcd and you just feed in the filament.
You can use the printer with the upgraded extruder and without the MMU. But you lose the filament runout function.
RE: Minimal rolling back from MK3S-MMU2S to MK3S
I finally took some time to read the MMU manual. https://cdn.prusa3d.com/downloads/manual/prusa3d_manual_mmu2s_en.pdf
Looks like Prusa has even thought about removing the MMU and put it in the manual. (page 30)
If you wish to print without the MMU2S unit installed, there are two possible options:
1.The easiest way is to use the printer as it is. So leave the extruder in MMU2S version. In that configuration, the filament IR sensor detects the absence of filament when it is almost under the Bondtech gears. This means less reliability of the filament unload. But in most cases, the unload will be successful. If the filament gets stuck under the Bontech gears, just use another piece of filament to go through.
2.The more reliable and also more difficult is to rebuild the extruder to Original MKS3+/ MK3S version. See the assembly manual, how to do that. We recommend this solution only if you are planning to unmount the MMU2S permanently.