Remove the AAA battery and back cover.

Insert a spudger into the seam of the top cover. Using a metal spudger may leave scratch marks, so you may choose your preferred tool.

In the image, you can see two clips on the top cover (marked with red circles). Use a spudger to release them, then lift the top cover. There is also a hidden clip at the rear that can be easily disengaged. (marked with orange circles)

After that, remove the three T5 screws (marked with green circles) to lift off the mid-frame.

Remove the three Phillips screws, then carefully separate the motherboard from the scroll wheel to complete the disassembly.

Measure the scroll wheel dimensions; you should be able to find the corresponding model online. I cleaned it using electronic contact cleaner, and the scroll wheel returned to normal. You can give this a try.

Finally, measure the button dimensions for future reference.

My English is not very good, so I used AI to translate this article into English. Please help correct any translation errors if there are mistakes.