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MMU2S not Selecting  

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Seth Tbdeaux
(@seth-tbdeaux)
New Member
MMU2S not Selecting

I have rebuilt my MMU2S now 4 times. I have replaced the Selector Motor, Entire Pulley Body, blades, Selector Body, and electronics. I have put silicone grease on the guide rods. The Selector will not drive to any filament. I have performed adjustment to both sensors. The printer works flawless otherwise. The idler is responsive and finds home on startup. The selector does not find home. Nothing has worked, please advise on anything else I can do before throwing more money at it.   

/R

Seth 

Posted : 14/11/2022 11:31 pm
Thejiral
(@thejiral)
Reputable Member
RE:

So after MMU startup and homing. What happens if you press the right of the three buttons on the MMU? (If nothing is happening at all, maybe you have to press the button a bit longer)
It should do a homing and then subsequently move idler and selector one position towards the right. Does it do that, is only the idler moving to that position but the selector isn't? If it isn't is the selector motor moving at all or standing completely still? What are the light signals showing?

This post was modified 2 weeks ago 3 times by Thejiral

Mk3s MMU2s, Voron 0.1

Posted : 16/11/2022 10:25 am
Thejiral
(@thejiral)
Reputable Member
RE:

If your Selector motor is never moving also not during homing, even though the idler is and no error light signals are given (and all sensors give the correct signal). I could think of two issues:
* MMU board defect
* motor cables/connection
* Undervoltage issue. I never had that one and I don't quite understand the electronics behind it but there is a very long thread around here on that issue. There seems to be a design error on the board which can (but doesn't have to) cause troubles.

This post was modified 2 weeks ago by Thejiral

Mk3s MMU2s, Voron 0.1

Posted : 16/11/2022 10:32 am
Seth Tbdeaux
(@seth-tbdeaux)
New Member
Topic starter answered:
RE: MMU2S not Selecting

Thejiral, 

Thanks for the interest.

-When pressed the MMU2S seems to be doing a homing sequence electronically. The lights flash and it cycles through the selections. Mechanically, the MMU does nothing. I tore it down again, nothing is binding, and after replacing the parts 3 times I didn't expect it to.   

-The Idler surprisingly doesn't move the the next position either. The only motor piece of the whole MMU I have not replaced is the pulley motor. All printer parts are replaced, the other two motors are replaced, the Finda probe, the electronics board, and the electronics board. 

-The selector motor is not moving for any reason, home or next filament. I have tried on the MMU board and using the Rambo software to load filament. 

-The light signals are consistent with filament load error. When it goes to actually load filament, but before the lights seem to appear to home the selector. The green light is driven to the 5th selection then back to the filament to be loaded. 

I will look into the under-voltage issue. I read he was able to supplement the driver voltage with an external source via usb. Thank you for the help. 

/R, Seth

Posted : 17/11/2022 1:02 pm
Thejiral
(@thejiral)
Reputable Member
RE:

One thing you can try, just to check if the selector sensor is working fine is to have no filament installed. After turning on the printer and MMU, once it is done with whatever it wants to do for startup, press the middle button for a few seconds. That should start the loading probably with a homing before if it is the frist proper action it does. No matter where your selector and idler really are or if they have been moving or not, when it is trying to get the filmanent insert a piece of filament from the other side (tubing needs to be removed between selector and extruder for that) until you hit the ball, then pull it out again. Does the MMU accept that then as successfully loading and respond with a constant green light at whatever position it thought it was loading?
If it is green, what happens if you are pressing the right or left button? Does the light jump by one position in that direction? But neither idler or selector?

If the fake loading works, if just the lights are moving and nothing else. I don't think your problem are the motors themselves. Especially if two and not just one motor is not showing any signs of life. If the cables are wired wrong, you usually can see at least a bit of tortured vibration for a short moment instead of proper movment. As you don't seem to see that, that's probably not the issue. One can also check the two phases for the correct resistance. I'd have to look it up what it should be but that way you can identify any shorting in the motor which I would not expect to be the problem here though (but which can fry your board).

Maybe I am wrong and overlooking something but to me this looks like a board issue of one way or another. I would suggest to you, to maybe state your case in the undervoltage thread too. Maybe that is your issue after all.

Mk3s MMU2s, Voron 0.1

Posted : 17/11/2022 8:37 pm
lennybotsford
(@lennybotsford)
New Member
RE:

Your comments are highly appreciated. Even if your point is wrong, it still has a right in it. All comments are proof that the original problem has been clarified.

 

Posted by: @seth-tbdeaux

Thejiral, 

Thanks for the interest.

-When pressed the MMU2S seems to be doing a homing sequence electronically. The lights flash and it cycles through the selections. Mechanically, the MMU does nothing. I tore it down again, nothing is binding, and after replacing the parts 3 times I didn't expect it to.   

-The Idler surprisingly doesn't move the the next position either. The only motor piece of the whole MMU I have not replaced is the pulley motor. All printer parts are replaced, the other two motors are replaced, the Finda probe, the electronics board, and the electronics board. tiny fishing unblocked

-The selector motor is not moving for any reason, home or next filament. I have tried on the MMU board and using the Rambo software to load filament. 

-The light signals are consistent with filament load error. When it goes to actually load filament, but before the lights seem to appear to home the selector. The green light is driven to the 5th selection then back to the filament to be loaded. 

I will look into the under-voltage issue. I read he was able to supplement the driver voltage with an external source via usb. Thank you for the help. 

/R, Seth

 

This post was modified 1 week ago by lennybotsford
Posted : 24/11/2022 4:10 am
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