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cheesestraws

Kensington Turbo Mice: A Tale of Two Trackballs

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I recently picked up a Kensington Turbo Mouse Plus trackball, which is the version of the Turbo Mouse that speaks the Mac/Mac Plus quadrature mouse interface, rather than ADB.  It also came with a spare ball, which meant I could get my ADB one also back up and running.  So I have given them both a clean and a lubricate, and I thought while I was in there, I'd document how to get into them and what's inside them for anyone else with one.

 

I'm going to put the pretty picture right at the top, though: this is a photosensor in a completely clear DIP case in a right-angled socket.  I really think this is cool.

 

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Disassembly/"teardown"/getting in is easy.  There are four screws on the bottom.  Two of them are under the label.  The label is foil, so you can get it off without damaging it reasonably easily.

 

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On the ADB 4.0 there are also two lubrication holes under the label that you can use to lubricate the rollers without taking the lid off.  In my case, this meant that the back of the sticker was revolting at least in those two areas and was covered in grotty coagulated oil and fluff.  So that was pleasant.  With those four screws out, the top of the case just lifts off.

 

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(First image: Turbo Mouse Plus 3.0; right image: Turbo Mouse ADB 4.0)

 

To get the PCB out of the case, you also need to undo an extra screw under the "prosthetic" third roller, the one that's just there for support.  On the 4.0, you can pop that roller out of the ball housing to make it easier to get to it.  On the 3.0, it doesn't look like you can, but it's not too awkward to get out anyway.  I took off the ball housing too to get some photos of the PCBs:

 

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Turbo Mouse Plus 3.0 PCB

 

 

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Turbo Mouse Plus 3.0 PCB

 

Obviously there have been simplifications, but the sensor mechanism and mechanics are very nearly the same.  The pretty transparent DIP chips have been replaced with single-in-line sensors, though, which is more sensible but much less fun.

 

I just used sewing machine oil to lubricate the bearings a bit; I'm sure there are better options but it's what I had.  Now they're not quite as smooth as the optical Expert Mouse I use as my main pointing device, but they're surprisingly close.

 

Hope this infodump/photodump is of use to someone!

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Embedded Microsystems did a much better job with their silk screening than Kensington (or whoever they went with later on.)  Or did they use gold traces?  Either way, looks nicer.

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On 8/2/2020 at 1:02 PM, cheesestraws said:

On the ADB 4.0 there are also two lubrication holes under the label that you can use to lubricate the rollers without taking the lid off.  In my case, this meant that the back of the sticker was revolting at least in those two areas and was covered in grotty coagulated oil and fluff.

Oh, is that what those holes are for? I assumed it was explicitly to catch that gunk, as opposed to letting it clog up the rollers and interior.

 

I need to oil mine. Do I just drop some oil on the ring and spin the rollers for a bit? Not sure what I have around, maybe some bike chain lubricant if I can find it…

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Cool breakdown, thanks for posting this. I've got a 4.0 that has some problems tracking horizontally. I also noticed that my photosensors (SD1 and SD2) are bent 45 degrees back, but when I tried putting them straight up and down like yours it didn't seem to have an effect. Clearly someone else before me got in there and did something. Any idea what I should try to do to get it working?

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11 hours ago, sfiera said:

Oh, is that what those holes are for? I assumed it was explicitly to catch that gunk, as opposed to letting it clog up the rollers and interior.

You may well be right here, actually.  I just had lubrication on the brain when I was looking at it and thought 'oh, you could lubricate the wheels through those, probably'.  Your theory is more plausible.  It certainly works, anyway... the back of that label was disgusting!

 

11 hours ago, sfiera said:

I need to oil mine. Do I just drop some oil on the ring and spin the rollers for a bit? Not sure what I have around, maybe some bike chain lubricant if I can find it…

That's what I did, and it worked really well.

 

11 hours ago, JohnnyLoquat said:

Any idea what I should try to do to get it working?

I would probably try the following three things:

  1. cleaning the textured side of the relevant roller with IPA or similar.
  2. check that light is actually coming out of the LED, probably by sticking another photosensor in the case loose aimed at the LED
  3. Stick an oscilloscope on the legs of the photosensor to see what the pulses coming out of it look like

That said, I am not in any way an expert on servicing these things: I just needed to lubricate them and thought I'd take some documentation pictures when I'm in there as there seems to be a bit of a shortage of information out there about their innards.

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On 8/3/2020 at 9:48 AM, cheesestraws said:
  1. cleaning the textured side of the relevant roller with IPA or similar.
  2. check that light is actually coming out of the LED, probably by sticking another photosensor in the case loose aimed at the LED
  3. Stick an oscilloscope on the legs of the photosensor to see what the pulses coming out of it look like

For checking the light: cell phone cameras are typically more sensitive to IR than human eyes are. It’s a good trick for checking the batteries of a remote control, just point your phone at it. It works similarly well for checking the trackball LEDs:

 

 

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