Personal: Custom Mechanical Keyboard

Feb 2024 - June 2024

Background

As I was leaving my previous job, I received this amazing keyboard as a gift. I expected it to work right out of the box so I plugged in the USB-C to power it. The USB power broke off of the PCB and I was distressed and asked my friend what should be done. He said I could redo everything. I had never worked with electrical components outside of school projects so I was hesitant but I'm really glad I took the leap to try things out.

The problem:​

USB-C port broke off the PCB board and the pins were pulled and broken in a way that it can't be easily resoldered. Potentially pads were torn? I had a person attempt to resolder it but they made it worse and burned the connectors.

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The solution:

Remove solder from all switches and replace the board. Modify for sound after ensuring everything works properly.

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I have never soldered for any of my projects outside of my design and discovery class. Reminding myself of the intricacies was pleasant and meditative. I signed up for a local makerspace called Bloominglabs to use their facilities and soldering iron setups. A proper solder sucker makes a large difference in the efficiency and pulling aspect of each switch. This PCB was a non-hotswappable board which meant that each pin for all 61 keys had to be removed by heating up and sucking the solder out of the board. Every 10 or so keys I'd feel there was improvement in my technique and efficicacy.

All the switches had been pulled off and I started resoldering the switches onto a new KZ60 PCB from Drop.com. When testing it out, it worked perfectly because I wasn't typing sentences and just clacked away. However when I typed on a keyboard tester I saw that certain keys would phantom press or stay pressed until I typed another key like "tttttttttttttttttttttttttttt". That really worried me and I pulled them out and started my troubleshooting process. 

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Troubleshooting:

- Unplugged and replugged (basic powercycle)

- Tried on different device from laptop to ipad (is problem isolated to one system?)

- Removed keycaps and identified which ones were acting up (what are the issue parts?)

- Switched the key switch with a regular functioning switch. The problem moved with the switch. (Issue is isolated to the switch and likely doesn't come from the board.)

- Bought new switches and compared how a good switch looks vs the bad switch

- Identified the common factor in bad switches was a crumpled or torn black film square in each switch. I suspect it is used to terminate the signal when the switch returns to a non-pressed position)

- Replaced problem switches with new switches. New switches sound different so moved them to function keys and not the alphabet keys.

Takeaway:

Torn black film was a result of poor solder sucking leading to excess force when pulling the switch off the plate. The excess force led to improper pulling that crimped the terminating film.

I'm very grateful to my friend who gifted the board to me even though it didn't work out and I had to rebuild it. He helped me along the way and I learned a lot about keyboards and the deep world behind it. The modular aspects really impress me and everything with the sound of the board fascinates me. I added masking tape onto the back of the PCB and foam to the bottom of the mounting plate to create a deeper sound. 

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It sounds and looks great I'm so happy with how it turned out!