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Fix a Spektrum Transmitter Using a Mouse

Scroll Wheel Psychosis

My old Spektrum DX6I has/had the dreaded “scroll wheel psychosis”!  I thought It was me not being able to do the simplest of programming set ups.  But, no. It was a random, faulty rotary encoder on the scroll wheel. A quick internet search zeroed in on the problem. . Thanks to all that pioneered before me I was able to fix my transmitter by sacrificing an old computer mouse! Basically, I removed the rotary encoder from a computer mouse scroll wheel and trimmed it down from 10 mm high to 7 mm high and re-soldered it back onto a small board inside the transmitter. I could have bought a new rotary encoder, but right now they are kinda hard to get unless you want a minimum order and pay shipping. Hey, I had a mouse and this whole affair took less time to do than it is taking to write it up! So here are the pictures.

An old Dell computer mouse with a mechanical rotary encoder. Note that Logitec mouses(mice?) use laser encoders and will not work.

This is the rotary encoder. Note how high off of the board it is. 10 mm to be exact. This will need to be cut down to 7mm with a Dremel and a magnifying hood. ( hey, old eyes).

Old mouse with de-soldering wick and harvested rotary encoder.

Close up of the encoder and a random switch.

The packaging is a wonderful place to perform the surgery. Six screws for the back, 2 screws for the encoder board and places for the batteries! Nice and easy! I only had to un-plug one harness.

This is a close-up of the scroll wheel board.  Two screws and one connector is all there is.

I tried contact cleaner on the encoder but it did not work.

Here is the trimmed down encoder soldered to the scroll wheel board.  The Dremel work did require a bit of magnification  but not too bad.  Like I said, if I could have bought a new component I would have but these are “the days of Covid19” supply chain disruption.

A side view next to the old rotary encoder on the right. The scroll wheel is level and is good to go!

All  buttoned up and ready to go. I included this picture as these Eneloop batteries are 10 years old and still hold a very long shelf life charge and , as far as I can tell, they still have all of their capacity as well.  I can recommend them and I would buy them again.


This fixed my problem !  The transmitter scroll wheel is now rock solid with no more skipping and random loss of input problems that it use to have.