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PotatoFi
(@potatofi)
Active Member
Rotary Encoder Part Number

I bought my Prusa MINI On the day it was announced. Unfortunately, the rotary encoder barely works and needs to be replaced. I figured out that they're an "EC11" encoder, and bought one: but it's through hole and taller than it should be.

I pushed ahead, flattened the legs and soldered it in. While it works, it unfortunately is way too sensitive - it skips every other menu item and icon.

Is there any documentation from Prusa which describes what kind of rotary encoder this is?

Best Answer by Kurvalak:

You probably found a solution by now, but I am in the same situation. Bought the prusa Mini almost after its availability and slowly but surely, the rotary encoder started missing 'steps' as I slowly built frustration. As many, when I realized I needed to do something, I was out of warranty (Prusa support was nice, but it is what it is). I did tried to see if printing filament was jammed in the rotary piece, did cleaned with electronic contact cleaner, but it did not improved the behavior of the rotary encoder. Here in Canada, the whole interface module is quite pricey (72US$ + shipping + tax), but at least can be found locally.

Before committing that kind of money, I thought I could try to de-solder the faulty one and re-solder a new one (we are makers after all). I looked for the EC11 encoder and it seems to be a model from Alpine, although searching for Alpine EC11 Rotary Encoder don't show any that would match what we have in the Prusa Mini. I can't find a surface mount type that looks similar. It seems I could pull the taps with one of these models, but I finally found a model that seems to work from Same Sky, series RIC11. The RIC11-31S10K3-GSMT (link to data sheet) seems to fit visually (even the two pins that are going through the PCB). Unfortunately, we don't have specs from Prusa for this part and I'm probably short of few electronics skills to validate if it will work from the data sheet (voltage, resolution, output, etc.). Nevertheless, I ordered one (seems to be available from many electronic stores (mouser, digi-key, etc), I'll try it, hoping that my soldering skills will be enough and I'll share the result here.

Here are some pictures of the prusa rotary encoder, a.k.a "The-frustration-decoder", for comparison with the data sheet :

Rotary Encoder Vertical View Rotary Encoder Side View Rotary Encoder Back Pin

Opublikowany : 28/01/2022 11:08 pm
1 ludzie polubili
Kurvalak
(@kurvalak)
Eminent Member
RE: Rotary Encoder Part Number

You probably found a solution by now, but I am in the same situation. Bought the prusa Mini almost after its availability and slowly but surely, the rotary encoder started missing 'steps' as I slowly built frustration. As many, when I realized I needed to do something, I was out of warranty (Prusa support was nice, but it is what it is). I did tried to see if printing filament was jammed in the rotary piece, did cleaned with electronic contact cleaner, but it did not improved the behavior of the rotary encoder. Here in Canada, the whole interface module is quite pricey (72US$ + shipping + tax), but at least can be found locally.

Before committing that kind of money, I thought I could try to de-solder the faulty one and re-solder a new one (we are makers after all). I looked for the EC11 encoder and it seems to be a model from Alpine, although searching for Alpine EC11 Rotary Encoder don't show any that would match what we have in the Prusa Mini. I can't find a surface mount type that looks similar. It seems I could pull the taps with one of these models, but I finally found a model that seems to work from Same Sky, series RIC11. The RIC11-31S10K3-GSMT (link to data sheet) seems to fit visually (even the two pins that are going through the PCB). Unfortunately, we don't have specs from Prusa for this part and I'm probably short of few electronics skills to validate if it will work from the data sheet (voltage, resolution, output, etc.). Nevertheless, I ordered one (seems to be available from many electronic stores (mouser, digi-key, etc), I'll try it, hoping that my soldering skills will be enough and I'll share the result here.

Here are some pictures of the prusa rotary encoder, a.k.a "The-frustration-decoder", for comparison with the data sheet :

Rotary Encoder Vertical View Rotary Encoder Side View Rotary Encoder Back Pin

Opublikowany : 22/06/2025 6:52 pm
2 ludzie polubili
Kurvalak
(@kurvalak)
Eminent Member
RE:

Well, desoldering was quite hard. I tried flux, adding solder, increasing temperature and I was not getting anywhere. I finally was able to do it using ChipQuik flux and low temperature solder. It worked like a charm.

The new part I ordered and referenced in my earlier post is slightly shorter than the original one, but otherwise, it is a perfect fit for the holes in the PCB and the pads. Once soldered, I plug the interface and it is now working perfectly (my mind wants me to believe that it is even better than the original part). 

So, hopefully it will be useful for anyone looking to replace the rotary encoder without replacing the whole interface.

PCB with desoldered part Old and New Rotary Encoder New Part Soldered

This post was modified 1 week temu by Kurvalak
Opublikowany : 26/06/2025 12:24 am
3 ludzie polubili
PotatoFi
(@potatofi)
Active Member
Topic starter answered:
RE: Rotary Encoder Part Number

Thank you very much for posting your research and results!

Opublikowany : 26/06/2025 7:55 am
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