Soldering a hotswap pcb

Learning and discussion Custom keyboards
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This is something I’ve been curious about ever since getting the kailh sockets in hand and putting them on a pcb. If you look at the back side you can see the pins of the switches poking between the compression contacts in the socket. It should be possible to solder the switch into the socket for permanent installation.

Why might someone want to do this? The kailh sockets are rated for 100 changes. I was stress testing them and got bored at 20 changes. While 100 changes will probably be sufficient for most, I can imagine a scenario where the sockets wear out and leave the pcb pretty much worthless.

Another scenario may be that you have found your perfect switch and a non hotswap version doesn’t exist. Every time you swap caps you inherently end up pulling some switches out.

Whatever the reason, is it even possible?

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Turns out it is totally possible. I’m writing this post on the board from the above pictures. Getting the solder to flow down into the pin contact area is a little challenging. A very fine tip would make it easier but this is still quite a bit more time consuming than a normal solder pcb. It’s very easy to overload with solder.

Here’s a video showing the switches much more secure to the pcb.

Would I do this again? Not if I can avoid it. It’s time consuming and a bit challenging. This would be a great fix to a loose socket thought (provided you don’t want to change switches anymore).

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Thanks for this! It’s reassuring to know that a hotswap pcb isn’t totally dead once the sockets begin to fail.

How does the difficulty compare to desoldering the sockets and soldering new ones on?

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I’ve never changed the sockets on a hotswap pcb but I feel like that would probably be a bit easier. The pads for the sockets are quite large.

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I don’t know if you would call it “wearing out” or not, but I have had to repair 2 or 3 sockets on my boards. What happens is that some switches have one very fat pin that opens up the compression leafs on one side of the socket. Then, when you swap to a switch that has thin pins, it either chatters like crazy or no longer registers. Pretty simple solution is to use some sharp, fine tweezers and push the leaf back down towards the front of the PCB.

But yeah, I can totally see where soldering might be required eventually… like in a decade or so.

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I wonder if someone could produce a hot swap socket that has a coil spring pushing the contacts together. That way, you have the leaf spring (the actual contact) being supported by a coil spring, which would make it much harder to damage a socket.

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