How do I clean/repair a rotary encoder?

Question

I have a mouse wheel that's acting up and even after taking it apart and cleaning it inside out very well, there seems to be some dirt inside the rotary encoder of the mouse wheel. Blowing it with air didn't help.

I have cleaned potentiometers before using IPA with success and I noticed it has similar tabs so I'm guessing you open it up the same way as potentiometers.

I've heard there's optical and mechanical encoders but I'm not sure what mine is. My guess is that if it's optical it will have a transparent disk inside it but to that I have to unsolder it. I have put this on hold to plan it a bit first and make sure I have all the materials I need for the repair.

Is it ok to use IPA to clean a mechanical encoder or will it mess up any lubricant that's inside? And if it does (and assuming there's no better option) what kind of lubricant should be used after?

Same if it's optical: Will IPA ruin the print on the disk or is it safe to use?

Any further advice on repairing rotary encoders would be much appreciated as I recently started working in repairs and although the most common way to go about it is to replace the part, I'd like to be able to repair it (because of an interest in vintage synth repairs where parts are very often obsolete or hard to find).

As requested, a couple of pics of the encoder:

Answer 1

It's difficult to tell, but your encoder may be a simple contacting type. I tore one of these down - as pictured.

It should be possible to clean this without stripping it down, using WD-40 or similar. (On the other hand, if it's an optical type, WD-40 may dissolve the optical pattern!) Good luck!

Answer 2

Answering my own question just to share the experience with people who might come across the same problem since my mouse wheel now works perfectly.

Fixing (or rather) cleaning the rotary encoder turned up to be a very easy task. In fact, taking it out of the PCB was much more challenging than cleaning it (and a little harder than I was expecting).

After removing it, I opened the metal tabs that hold everything together using a small straight screwdriver. I found that it opens up much neater if you hold it so its side is against the desk. This way, you can over-bend it because it will hit the desk when it's exactly straight.

Just like hernos said in his comment (Thanks hernos!), it was a simple mechanical encoder, so I felt it was safe to clean it with IPA and a small brush.

I used plenty of IPA, until everything was fully wet with it and not only did it dissolve the dirt, it also seemed to collect the dirt inside the pool of IPA on the desk under it.

The dirt was consisted mainly of really thin bits of hair, so I doubt if spraying contact cleaner of WD40 would have worked as well without opening the encoder because the dirt would be stuck in there.

Finally, I put it back together and cleaned its legs from the old solder and re-tinned them before soldering it back to the PCB.