Maintenance/Mouse button replacement

Background and problem

I'm your ordinary sort of office worker, who types and clicks far too often in the course of a day. Various body parts connected to these devices are getting old and very much appreciate that my employer has supplied me with a mid-range ergonomic keyboard and mouse. Office workers of the world, you are advised to ask for at least this much. I think I'm emotionally attached, perhaps it makes me feel fancy that someone spent one hundred euro on me, or one must perform one's longevity once the job becomes a career, like a delivery driver hanging a pair of fuzzy dice over the rear-view mirror after pulling away from headquarters.

The mouse trouble began when I moved into a "home office"—we'll spare most of the details except to say that my standing desk is not much more than a cutting board screwed to the wall at navel height. This is the perfect height for extremely destructive impact of any plastic-encased electronics unlucky enough to fall to the floor, and small enough that this happens often. My mouse has suffered and its once-noble exterior is held together either by gravity or by a small number of the original fasteners. But it still clicks!

At least, it clicks most of the time. Where this inconsistency really starts to burn is double-clicking, which is an ableist-enough exercise under normal circumstances and a fool's errand with iffy buttons. For the past year, I've software-mapped the right and left buttons to switch them, and I hold the mouse in a funny way which lets me imagine that everything is fine, sort of. It's also causing my habits to cross-wire, and anyway I find that the right button becomes increasingly important in proportion to how much I can't use it.

The keyboard and mouse are a thing together, but e-waste if separated. I'd really like to make the mouse work again for the sake of the planet if nothing else. It's just so much junk to produce and reproduce otherwise.

Pop the hood

Something's rotten about these microswitches

I measured missed clicks with the linux utility xev and it showed that the buttons had become sensitive to the exact orientation of my finger. Either something was wrong with the alignment of the broken plastic parts, contact material was worn off of the internal switch, dust sand and chips had gotten in, or all of the above. First thing to do is just put it back together, next I cleaned the stray lint, squirted air all around and flooded the button with isopropyl, finally imagining very hard that I had fixed the issue, yet still nothing changed.

Firmly stuck in the honeymoon phase, I believed that a light repair would involve a quick business of swapping out the standard microswitches (silver squares with an orange dot in the middle). They seem to all come in the same vanilla flavor since long before this particular thing was made ten years ago. All 8 solder points are accessible as you might see in this image.

I confirm that the switches have the same pinout and footprint as the potential replacements, although the proof will not be definitively in the pudding until the switches are isolated from their circuit.

A fellow Earth defender in my office's IT department orders the new switches and I barely remember the next couple of weeks of missed clicks.

Prying the switches off

What could possibly go wrong?

To desolder the switches with a single-headed iron rather than a hot air setup or a double-headed iron, I relied on the versatile thumbtack to apply some pressure to the joint as I heated up each pad in turn.

In hindsight, I relearned the lesson that coffee and fine motor work mix poorly. My hands were trembling like leaves and I probably used ten times the force that I should have when pushing the thumbtack under the switch. I also should have pried only at the legs and not at the body of the switch itself.

As you have probably guessed, gentle reader, I tore a bunch of important and small electrical traces off of the top of the board during this step.

Here are some photos of the damage:

Removing the original microswitches has wounded their host

There should be no brown visible, this shows that electrical traces were torn away.

It's a bit like discovering that some bits of a placenta are missing after birth, this is going to be a serious problem and we cannot continue without knowing exactly what went wrong.

Internal schematic for a microswitch

Nonetheless, I thought I would give it a try. After all, the internal wiring for these switches has the left and right pads tied together internally so the circuit board only really needed to have one pad conducting the signal and the other could have been purely for mechanical attachment, which would also explain why the exact same pads tore more easily on each switch.

The new switches went in but I am not proud of my work. I should mention at this point that I'm a complete hack, an unlicensed hobbyist, I was let go from a summer job soldering for a hardware video artist decades ago and unwanted flashbacks of this experience singed my conscience as I sweated over installing the two small switches here.

Okay but it went uneventfully and here is the result now with handsome slate nubs:

New mouse same as the old mouse

There was a slight height difference between the old and new switches, so I was ready to sand down the part of the button which does the internal pressing.

Side view of old (left) and new (right) switches

This is where the story gets sad: although the mechanical clickiness feels really good now, there is no signal sent from either button. They are dead to the computer.

My photographer sees some pretty trees outside the window and mercifully snaps a few photos of that.

All is not lost.