Key switch soldering help

Modding
1

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:

image

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!

2

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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3

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?

4

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

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5

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:

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