First time building a keyboard. I'm not good at it. About 6 keys don't work. How do I troubleshoot/debug this?


01 Jun 2019, 20:16

Trying to build my first keyboard and I'm not having much luck haha.

Pics of the problem area:

It's my first time soldering so sorry for the eye torture.

It's a Quefrency board ( ... 2980861022) and I had to solder the diodes and micro controller on myself. I elected to use the Elite-C micro controller but it seems to be mostly the same as the Pro Micro.

After soldering it on and flashing the firmware the 2, W, S, and Z keys don't work (I'm only concerned with this left half of the keyboard currently).

- I tried desoldering these to see if it was the switches, but even if I use tweezers I can't get the keypress to go through.
- I've also tried reflashing the firmware multiple times.
- I used a multimeter to check the continuity with these tweezers and it indeed appears to work.
- I used the same multimeter in diode mode to check all the diodes on the board and they all read the same, around "750".

This is making me think it's the micro controller or the PCB. Maybe I got it too hot or something during soldering?

I took some pictures, is there anything that looks weird? Should I buy a new PCB or micro controller (is there a way to test if these are at fault)? Is it the soldering points? They all look shiny and appear to make contact with the pads.

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02 Jun 2019, 05:28

You might check soldering on the diodes to see if all of them are soldered properly.


02 Jun 2019, 09:33

You can also check the soldering on the controller, seems an entire column is not fuctionning (2 -W -S -Z)


02 Jun 2019, 09:52

Your problem sounds like one particular column has a bad soldering joint where it connects to the controller. I had that exact problem on my first build.

In your pictures it looks like the solder has not flowed properly down onto several of the pads. It is important when soldering that both metal surfaces are hot when the solder melts and flows over them: otherwise you'd get a "cold solder" joint that will break sooner or later.
This is extra important on keyboards because they get subject to lots of vibrations. Now and then you can see posts on forums about mass-produced keyboards that lose a row or column after a year of use, when an improperly made solder joint has broken.

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02 Jun 2019, 18:00

also double check the orientation of the diodes. they only work in one direction

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