Buzzing Mac is actually my Mighty Mouse

My Mac started to make this crazy buzzing sound, and it was bothering me for several days.  At first I thought it was the hard disk drive failing.  Then I thought it might have been the internal fan getting worn out.

Then I realized it was my Apple Mighty Mouse.  It was buzzing.  Making a racket.

Imagining how a mouse would buzz, I first thought it might be an internal electronic component about to fail.  But then I learned that the Mighty Mouse has a tiny a little speaker which makes a "click click click" sound as you rotate its tiny trackball.

That little internal speaker is now clicking all the time, dozens of times per second.  And the left/right trackball movement seems non-functional.  Ug, its REALLY ANNOYING.  The mouse is about 6 years old, so it could be an internal failure related to age, or it might have gotten a little, um, wet.

I'll open it up soon to see if there is anything I can do.  If not, maybe I'll just cut out the speaker circuit.  Alternatively, I might just buy a used Mighty Mouse.

I'll update this as I explore this thing.

Update 1: The Speaker in the Apple Mighty Mouse

Well, I've confirmed it.  I bought a used USB mighty mouse and fooled around with it.  I confirmed that the USB Mighty Mouse does have a speaker in it.  Here's a way to check it out!
  • Unplug mouse.  Roll trackball around and listen for the little clicks.  They aren't there.
  • Plug in mouse. Roll trackball around and listen to the little clicks.  Click click click!
Update 2: Take-apart of a USB Mighty Mouse

I don't really feel like tearing apart my broken Mighty Mouse, but something draws me to it.    I dig in, levering the outer ring off to get inside.  It's crazy dirty inside, with lots of long hairs and other garbage that you'd never think could make it into these very tight spaces.

There she is, a little speaker, making all that noise.   By disconnecting the scroll ball ribbon cable, the clicks stop.

The white round speaker of the Apple Mighty Mouse
I take apart the scroll ball mechanism.  It's unholy - scum and dirt all over.  I clean it out and remove just the cable.  It looks worn down and gross.  I clean it the best I can.  I plug in the cable - which has four sensors on-board - and it clicks the speaker.  ug!

The scroll ball mechanism seems to use four rotating magnets to sense scrolling, and evidently a hall effect sensor has failed.  So at this point, I re-assemble the mighty mouse with the track ball circuit disconnected.  Now it functions like an old-school mouse without a scroll mechanism.

The very dirty track ball cable, with four embedded sensors

Update 3: Into the Parts Bin

I bought a working used USB Mighty Mouse on eBay.  It was under $10 and it works great.   My well-worn, semi-functional Mighty Mouse goes into the parts bin, for future cannibalization, exploration, or eventual recycling.

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