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FINDA probe behaving erratically  

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DarkKnight
(@darkknight)
Eminent Member
FINDA probe behaving erratically

After perhaps 30 or so hours of printing without FINDA issues, the FINDA is now behaving erratically.

I have verified that the channel is clear and the ball moves freely in the channel. I have to pull the FINDA almost out of the channel to get the MMU2 to recognize that the filament is unloaded, however it will then not recognize that a filament is loaded correctly because it is out too far. I had it calibrated correctly, and while having issues dealing with filament loading properly because of other malfunctions, this started happening.

There does not seem to be a happy medium. I am left wondering why Prusa chose to use a Hall effect sensor instead of duplicating the apparently more reliable IR sensor setup already on the extruder.

There should be a way to get a reading from the sensor when having these issues. At a bare minimum an LED reflecting the binary state of the sensor is needed.

I’ve had 6 failed prints in a row since changing to a smaller nozzle and attempting to print with the MMU. Between the Slicer issues, and now the hardware issues, user experience makes this feel like a prototype grade product. Troubleshooting is difficult because of the overly simplified diagnostics available to the user when experiencing a problem. 

 

In the case of the MMU failing to detect a filament load properly at the MMU and filament makes it to the nozzle, WHY does it keep feeding the filament when the extruder should then see a filament presence? There needs to be programming in the firmware that can detect this. Something as simple as:

IF FINDA = 1 && EXTIR = 0

THEN ERROR = 5

 The MMU, as error prone as it is would benefit from a simple 7 segment status code LED.

Lastly, while troubleshooting this problem, the screws fell out for the millionth time and now one of the springs seems to have fallen into a black hole. Is a flipping retaining mechanism for the screws too much to ask for? Printer is completely unusable now do a single spring, for which a spare wasn’t provided and it isn’t even mentioned in the parts list on the back of the page that includes all of the other parts.

 

Prusa, you can do better than this.

Posted : 03/03/2021 3:58 am
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