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Selector Motor Doesn't Move the Selector  

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sfshook22
(@sfshook22)
Active Member
Selector Motor Doesn't Move the Selector

I am having a problem in that the selector motor doesn't turn and therefore the selector doesn't move.

I have ensured that there are no blockages.

I can turn the geared rod by hand and the selector moves.

The selector doesn't calibrate the end points.

I have re-flashed the MMU just to make sure that it didn't get corrupted some how.

None of the connections are lose.

I have followed all of the suggested trouble shooting guides in the user guide.

I was almost through printed a test block with 5 different filaments and it was working great but in about the last 5% or so the selector motor quit working.

Any suggestions would be a great help.

Thank you,

Steve

Posted : 07/07/2019 12:39 am
osbock
(@osbock)
Eminent Member
RE: Selector Motor Doesn't Move the Selector

I hate to sound like a parrot, but IR calibration is 97% of all the problems in the MMU. Personally, I had it working fine most of the time but every once and a while it would glitch, and all hell would break loose . Note: I'm not positive I have it fixed, it's a sensitive bugger.

 

Posted : 07/07/2019 2:56 am
sfshook22
(@sfshook22)
Active Member
Topic starter answered:
RE: Selector Motor Doesn't Move the Selector

Kevin,

Thank you for the reply, but we determined that it is most likely that the mmu's electronics board is at fault. When the selector motor is swapped out with the pulley motor the selector motor works and then the pulley motor doesn't.

Have a nice day,

Steve

Posted : 07/07/2019 3:07 pm
Dave Avery
(@dave-avery)
Honorable Member
RE: Selector Motor Doesn't Move the Selector

selector wont move if the IR or finda sensors think there is filament in the path. you can check the sensor state under support/sensors

Posted : 07/07/2019 4:22 pm
Mordiev
(@mordiev)
Active Member
RE: Selector Motor Doesn't Move the Selector

I just ran into this exact same problem.  You guys were really close but one of the details were off by just a little bit.  

Let me explain the behavior.  Reboot the printer and the MMU will boot up and home the Idler drum.  LED 1 shows green.  At this point the selector has not been homed.  It can be moved manually by spinning the 8mm threaded Leadscrew.  (Assuming there isn't any filament blocking movement.) If you press the right button for try to select a filament to load from the LCD screen/Gcode the MMU will blink a few lights indicating that it is about to home the selector.  But then it stops and blinks all five LED lights red.  They will continue to blink red forever.  

Factory reset doesn't help, Firmware upgrade doesn't help.

The problem is the FINDA sensor thinks there is filament loaded so it refused to allow the selector to move.  Because the sensor says 1 or high.  David you were correct that you can open the LCD Support > Sensors menu but that seems to be frozen.  It doesn't update.  It will say the FINDA is 1 forever no matter what you do.  So don't look there.

Instead focus on the blinking LED lights.  Red means the Sensor is detecting filament.  Green means it is clear.  So clear out any filament and/or debris that might be causing your issue and when the LED lights are green you are good to go.  Just reboot the MMU with the reset on its side or reset the entire printer and you are good to go.

THANK YOU ALL very much for the help.  I was worried I needed to replace the board as well.

Posted : 26/07/2019 3:29 am
richard.l liked
gnat
 gnat
(@gnat)
Noble Member
RE: Selector Motor Doesn't Move the Selector
Posted by: aaryn.e2

Instead focus on the blinking LED lights.

Actually there is a better and more easily understood option. Look at the top of the FINDA itself. Like the PINDA it has an LED that changes state based on what the sensor sees. It is dimmer than the PINDA, however, so I find I have to cup my hand around it  to see it well. If it is lit, there is no filament. If it is dark, it thinks there is filament.

MMU tips and troubleshooting
Posted : 26/07/2019 3:13 pm
sfshook22
(@sfshook22)
Active Member
Topic starter answered:
RE: Selector Motor Doesn't Move the Selector

Gnat,

I actually got it to work. It was a combination of adjusting the chimney flag and the FINDA.

I used the "support -> sensor" selection to make adjustments. You don't have to depend on the lights.

Chimney Flag - Had to shave it off in order to adjust it so when no filament is present the IR sensor show "0". When filament is present is present it will show "1". There wasn't enough movement in the method in the handbook.

For the FINDA:

I put a piece of filament in and adjusted it so that the sensor showed "1" then moved it up until it read "0". Then moved it down about half way and ensured that it would read "1". Removed the filament to ensure that it read "0".

It was much easier to make the adjustments using the "support -> sensor" than the method shown in the handbook.

Also there is a bug in the firmware (which was reported and verified" that the FINDA doesn't report the correct reading when printing. When the filament changes the reading should be "0" but is still "1". PRUSA said a fix would come in the next update. It doesn't affect the printing.

Using the above method I haven't had a problem with printing from 1 to 5 colors yet.

Thank you for all of your help,

Steve

This post was modified 5 years ago by sfshook22
Posted : 26/07/2019 3:30 pm
Collin
(@collin)
Active Member
RE: Selector Motor Doesn't Move the Selector

I realize I am posting in an old thread I just wanted to say thank you all for posting your experiences with this.  I had this exact issue tonight and I probably would have given up and ordered another board until I figured out like you that it was the stupid PINDA.  Learned yet one more thing about this creature tonight.  I wish the sensor statuses showed on the main screen at all times it would go a long way towards knowing what the heck these things are doing sometimes.  

Posted : 12/01/2022 3:53 am
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