The things we use break all the time. More times than not, when something is “broken” only one or two component parts are actually broken. Often, the still usable parts can either be salvaged individually or the functional system repurposed in its entirety. Whenever tinkering with something–be it salvaging, repairing, or repurposing–it is important to have a good understanding of the major components within it and how they fit together both functionally and physically. Depending on what you want to do, the intricacies and even the exact way all of the components work are often irrelevant. You only need to have an understanding to the depth that you want to work, and if you don’t plan to take something apart, you can usually get by with only understanding how it fits in with the rest of the system. 

Salvaged switches

Salvaging:

My first mechanical keyboard developed a strange problem after a couple years of use. Generally, the keyboard would work, but occasionally, pressing the “enter” or “K” keys would output a random series of characters. 

Key switch (left) and keycaps (right)

Before I delve deeper, here is a brief explainer of the major components of a mechanical keyboard. First, is the case that holds all of the following parts. Next, the PCB, or printed circuit board, which holds the keyswitches (the part that actually presses down to signal a keystroke), and a microcontroller which registers each time a key is pressed. Keyswitches are either soldered (basically glued together with melted metal that solidifies when it cools) onto a PCB or “hot-swappable” meaning the PCB has special attachments so the switches can be added/removed without soldering. On top of the keyswitch sits the keycap, which is what you physically touch when pressing down a key. 

Based on my keyboard’s strange behavior, I could pinpoint the source of the error. The key switch only registers a binary state (pressed or not pressed) and does not determine the value of the output. Because there was output when the key was pressed, but not the right character, I knew that the switches were functional and that the PCB must be faulty. The keyboard as a whole was useless to me, but not every part in it was broken. With very limited options to repurpose or repair it, it was time to salvage.

First, I lifted off all the keycaps, which are both easy to remove and compatible with any other keyboard.

Salvaging the keyswitches was quite a bit more involved. The main benefit of a hot-swappable keyboard is that, well, swapping in and out is easy and solder-free. Unfortunately, my keyboard had soldered switches, so to salvage them I had to get out my soldering iron.

 Soldering iron (bottom), solder sucker (right), and PCB (background)

I had a very small amount of experience with soldering before this, but I had never desoldered before. The process of desoldering requires only two tools: a soldering iron and a solder sucker. First, hold the hot soldering iron against the soldered area until it begins to melt, then press the solder sucker against it, and release the plunger to suck up the liquid solder. From there, used wire snippers to trim off the LEDs and a pair of pliers to pull the out. Then, I just had to pull the switches off of the plate, and I had a pile of salvaged switches ready for use on a different keyboard. 

 Top of PCB showing switches and tools

The switches I salvaged are linear Red switches from the well regarded German company Cherry. They normally cost $3.50 for a pack of 10, meaning by salvaging the switches from this 110-key keyboard, I salvaged nearly $40 of fully functional parts ready for use in another project.