Key switch soldering help

Hi folks!

I got myself a second UHKv1 and decided to replace the switches. I’m no stranger to soldering, but I definitely wouldn’t say that I’m a pro either.

I started with one half and got a success rate of about 80%. I managed to fix a few of the faulty switches by removing them and soldering them again. But for 6 of them, I simply just can’t get them to work. Some of them seem to suffer from the “Insufficient Wetting (Pad)” problem as described in this Adafruit guide, and I ried cleaning them and solder according to the guide, without much luck.

Here’s a photo of the PCB for one of the problematic keys, from both sides:


Can somebody:

  1. Tell me how I ruined it (and hopefully also how to fix it again)?
  2. Draw on top of the photo and tell me exactly where the conducting part of the holes are, so I can make sure to focus my soldering effort?

Any help is greatly appreciated!

Hi there!

It’s worth removing the burnt flux first according to the Adafruit guide. Afterward, use some flux on the pads to improve wetting. Use a more aggressive flux if you don’t succeed with a mild one.

If there are broken wires, which cannot be told based on your photo, open the board in KiCad and use jumper wires.

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Thanks for a quick reply!

How do I tell whether there are broken wires? I have this feeling that I maybe pulled of the wire around the holes while taking out the old switches. Is that a possible cause for this?

Use a multimeter to do continuity tests and also use the KiCad board design.

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A jumper wire resurrected the first of them. Thank you so much!

I already really, really loved the open source aspect of UHK. Now at a completely new level :slight_smile: