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FINDA probe not working as expected  

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uli.b
(@uli-b)
New Member
FINDA probe not working as expected

I have an issue where the FINDA sensor works properly for a while and randomly after any issues with filament load at the MMU (MMU asking to fix issue etc...) the sensor stays in "1" status, no matter if filament is loaded through the sensor or not. Subsequent loads all fail as the filament gets pushed to the nozzle, IR is triggered and then the MMU retracts it again. After I reset the printer, FINDA is working properly again.

I'm on the latest firmware for both MK3S and MMU2S.

Posted : 16/08/2019 8:09 am
Dave Avery
(@dave-avery)
Honorable Member
RE: FINDA probe not working as expected

i use a modified selector that has a magnet below the ball - works great

http://www.thingiverse.com/thing:3688458

 

 

Posted : 16/08/2019 12:19 pm
roland.f3
(@roland-f3)
Active Member
RE: FINDA probe not working as expected

I have the same problem. The modified selctor will not help in this case, because the FINDA stays on "1" regardless what you do with it.
Even when you completely remove it from the selctor and there is no metalic element even near to it.
Only after a reset of the printer it will behave normally again, but this means a multi color print is gone, again.

Posted : 24/08/2019 9:20 pm
uli.b
(@uli-b)
New Member
Topic starter answered:
RE: FINDA probe not working as expected

I guess all that can be said about this has already been said here ( I think i missed this when I was looking for a solution):

https://forum.prusaprinters.org/forum/original-prusa-i3-mmu2s-mmu2-hardware-firmware-and-software-help/finda-stops-working-halfway-through-print-sensor-value-stuck-at-1/  

Posted : 25/08/2019 1:11 am
ahmed.s6
(@ahmed-s6)
Active Member
RE: FINDA probe not working as expected

may not be related but I ran into awful trouble with the sensor flipping to N/A during load and unload and then failing to load the filament. It seemed like only a hard reset will get it back, and then for only a short while. At one point I reseated the connectors to the MMU control board and that made a difference or a short while but the problem came back. The degradation happened over a period of time.

In frustration, I took the board out and looked at the connector soldering under a microscope. It seemed dry (bad connection) with insufficient solder applied. I took out my soldering iron, re-flowed the solder and added a little more to make strong joins.

So far ran for 40 changes in succession without a hitch! unheard of in my experience recently. Interestingly, when loading filament now the sensor still flips to N/A but loads fine and immediately flips to the correct value of 1 or 0.

Maybe Prusa has a marginal setting in their PCBA manufacturing where they have only selected the surface mount solder profiles and not applied enough material for the through hole connectors.

Hope this helps someone else.

 

Posted : 07/07/2020 9:14 pm
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