Encoder operation Reversed

Problem: I’ve just built my second Shruthi-1 digital board. Everything is working perfectly- apart from one annoying glitch.
The operation of the encoder is incorrect. When clicked, it does what you’d expect it to do when rotated, and vice-versa. I guess this is because two or more of the pins are reversed. This is incidentally, an encoder I got from Digi-Key, so hope you haven’t used the identical one I sent you, Mangros :frowning:

I guess I don’t have any option but to attempt to desolder the bastard. So… does anyone have a spare, by any chance?


Is that the CT3011-ND part? Did you have to modify anything at all to get it to fit? The one I have of that part number works good, but is too narrow to fit on the PCB properly. Although a little modding here 'n there would make it ok i think…

Im not sure how or why it would behave like that though!? But I do know that they are the same as x0xb0xes use, and problems with them are not uncommon…

It seems to be a bit of an issue getting good encoders at the moment :confused: And I need to get 3…

Someone reported the same problem 4 or 5 months ago. If you look for a 24 clicks encoder with switch on digikey, the part you’ll find looks like a good match, but if you look closely at the datasheet you’ll notice that the pinout does not match!

The part I ship with the kit are bought in hundreds straight from the factory. I only have a couple of those left - the rest is bagged for the next batch of kits.

From Mouser: PEC11-4215F-S0024 or PEC11-4220F-S0024 (depending on the shaft length you want).

Reichelt has the encoder that is specified in the bom, which actually doesn’t list the digikey part.

the Farnell one isn’t available for more than a month…

Thanks for the replies guys.
I’ve found some units that appear to be identical to the Reichelt one on UK eBay, so I’ve ordered a couple from there. Wish me luck desoldering the old one. I don’t have a good record on this…


Nope, there’s a good reason the Digikey one isn’t listed, rosch. I made exactly the mistake pichenettes points out, unfortunately.


trial and error :slight_smile:
i have some wrong parts in stock, too

Olivier, I recall reporting the Digikey part to you that used to be in the BOM (CT3011-ND), because it didn’t fit the PCB. Im sure it could be made to fit with some tweaking here 'n there. But it’s not ideal.

However, im almost certain it did actually work. I’ll have to test it again on my next builds…
Alx, can you confirm if that is the same part number you used? And what about the PCB fit issue?

Also, it shouldn’t be too hard to remove the bad part.
Don’t bother trying to remove it whole, as you’ll only make more work for yourself and risk damage to the PCB. Just cut the legs off close to the body of the part, then desolder each leg one by one, and clear the holes with a solder sucker after.

Yeah, trial and error…
I just didn’t realise there were different pinouts for encoders…
I’ve got the old one out now, anyway. Usual problem though. I can’t clear the solder from one of the holes in the PCB. Trying to get rid of those stubborn bits of solder is where I usually manage to trashed the pads on the PCB.


That 44-day lead time for the Farnell part hasn’t moved for at least a week now…

Damn it.

Alx, 2 tricks that can help… Add a little fresh solder to the hole, and try again. Fresh flows better than old. And more flows better than less, in my experience!
Or heat up a bit of wire with the soldering iron, (like a cut resistor leg etc) and push it though the hole. Quite often when you draw it back out, it will take the remaining solder with it, leaving the hole clear.

Do you not have any records for the part number of the one you have? It would help…

Mangros, I was almost excited to see that RS list the correct part! But then my heart sank when I saw that they have a similar lead time… Ugh.

I’ll let you know if the eBay ones are OK. They have the exact same Alps model number as the Reichelt ones though, according to the datasheet that’s linked from the eBay auction page, so I’m fairly confident they’ll be OK.

I actually managed to get the encoder out intact, but you’re right, Luap- I should have just cut it off the board, as you say. I’ll try the trick you mention to clear the hole. Seem to recall doing that once before.

Thanks, as ever, guys.


Oh, the Digikey part number is
P12336-ND (at $1.41)

I didn’t have any major issues getting it to fit, that I can recall.


Ahh well thats sort of good news then… (For future reference) That means you can use the part I mentioned as a substitute, so long as you can put up with 2 things.
The pins are 100% correct, except for the 2 shield legs. Which you’d have to bend about some in order to secure it well to the PCB.
Secondly, as I mentioned, it’s not uncommon to get a bad one (The switch would work, the encoder part could sometimes be ropey). When I used them in x0xb0xes, I’d make sure I had a spare to hand. Once it’s fitted and working though, they do seem to stay good.

It looks like I need to make a Digikey order anyway, so im going to put a couple on the order. I think they’ll do if I can’t get the others.

Luap if you prefer the right ones (bom) i can do a small reichelt order. i need one too, not now, though, but we get over the minimum.

Sure! When are you ordering? Im down for 3…
But I still need to do Mouser and Digikey orders. But not for much, so if you guys need anything from there, let me know.

i can do it tonight, then they’ll probably send it tomorrow.
let me know if there’s something else you like to add.

Sounds good rosch, thanks :slight_smile:
I don’t think theres anything else I need from there. Im pretty sure the few remaining parts I need I can only get from Mouser & Digikey now… (Button caps, more blue LCD’s and some particular capacitors)

Did you try the blue LCD, Luap? I’m really pleased with mine. The red one seems a bit dim in comparison, I think. I’d be interested to know what the other colours look like.


I’ve not tried the blue one yet, but if Oliviers picts are anything to go by then im sure they are great. I’ll need 2 more screens for the others im building, so I may as well go with the same blue ones.
I have a red one on my SSM Shruthi, and it’s good enough. And yes, a little dim maybe compared to some others. But there are so many different ones around, I wouldn’t know if it is the same as you have. Im pretty sure brighter/better red ones are available though. I think Olivier must have tried them all by now??