Switches not working

Learning and discussion
1

Just built my first keyboard but for some reason some of the switches are not working. The pins are for the most part straight and I can get a keystroke if I use pair of tweezers to short the pcb. Any help would be greatly appreciated.

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(The switches without keycaps are the ones that don’t work)

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Hello and welcome!

The first thing I would do in this situation is to try and rule out either the switches or the PCB and then go from there. These suggestions will be easier if the PCB is hot-swap, but still should help with diagnosis on a soldered PCB.

  • If it’s a soldered board, I’d check the underside first; inspect closely the joints for the non-functioning switches and make sure they aren’t bridging any other nearby components like diodes.

  • Try swapping one switch that doesn’t work with another that does - if the problem stays in the same place, it’s likely something with the PCB - if the problem follows the switches, it’s something with them. (Personally I think it’s more likely to be the switches, but it’s worth testing.)

  • If you have a switch opener, open one up and check if the contacts are touching when the stem is down (or removed).

    Red

  • Sometimes the bendy metal bit is bent too much, or out of place, or obstructed, etc. - if those two pieces aren’t touching at the little pad between them when the stem is down, the switch won’t actuate.

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3

Thanks for the response. I tried swapping out the some of the switches that didn’t work with ones that did but sadly it still didn’t work. I think it’s either the PCB (though I can get a keystroke if I short it out) or the switches aren’t fully In the PCB. If I press really hard on one of the switches to the point where I’m slightly bending the switch plate it works. Is there any way to fix this?

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Is this a hot swap board? It’s possible that the sockets aren’t making complete contact with the pins. Depending on the type of socket, you might be able to squeeze the contacts inside closer together with sharp tweezers, or possibly twist the switch pin so that it touches the socket contacts.

I’d take something like a flashlight and inspect the sockets; compare the working and non-working ones and see if the bad ones have more space between the metal bits inside the plastic.

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I got the switches working! I placed 2 stand offs wrong so the switch plate was slightly bent up. Thanks for all your help troubleshooting I really appreciate it.

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