The Logitech Trackman Marble FX probably has the strongest "cult following" of any pointing device. I've long since loved the logo off mine, and most of the texture (most of it is shiny now, and the left button has an indentation, just like several keys on my Truly Ergonomic keyboards).
Recently, the right button started to require more force and occasional wiggling to get it to work. Then it just quit. If you Google around, you find repeated references to these being impossible to fix.
You may or may not know that the buttons on a Marble FX are Matsu****a microswitchs: their dimensions are compatible with the Omron switches used in many modern mice and trackballs. Except for one detail. The two mounting holes in a Matsu****a switch this size are 2.0mm, and the Omron's are closer to 1.5mm. Normally, this doesn't matter, because I've never seen anyone screw down microswitches this size (will even a 2-56 screw fit?). But the right button switch (and only the right button switch) on an FX slides onto 1.5mm plastic pins and then is locked into place by two claws. So common wisdom is you can't replace it with an Omron.
Button transplants were wort of out of the question. I could have done a transplant with the red button (which doesn't do anything under Windows 8 or 10, but I use as a middle mouse button under Linux). A transplant with the upper button was out, of course, as that's my "convert to scroll wheel" button in Windows (thanks to X-Mouse) and in Linux (via input mode).
I could have done a double transplant, replacing a working Matsu****a from a different location with an Omron. But... 20+ year old switches. I didn't want to risk desoldering and resoldering a Matsu****a, only to end up with a dead switch when I was done. So, enter a six-pack of Omrons from Amazon for $5.
Obviously, I wasn't going to try to skinny down the pins: they're structural, and old. So...
- Let's try a tiny reamer, chucked in the fordom. No good, by the time the holes got to 2.0mm at the small end of the reamer, they were about 2.2 at the large end, and this made the thing wobbly. And I think I cut through the plastic wall of the switch. One down, five to go.
- How about using a tiny torx as a straight reamer. Nope, that cracked the plastic.
Third time was the charm. A 5/64 titanium drill bit, held gently in a flex-shaft, followed the original hole, and there was just enough plastic there so it didn't break through and let debris into the switch mechanism.
My FX is working again, although the left and right switch sounds are obviously different. I could tear it down again and replace the left switch, but I don't think so.
