geekhack
geekhack Projects => Making Stuff Together! => Topic started by: Photoelectric on Thu, 24 April 2014, 13:49:17
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Does anyone have suggestions for how to diagnose a few non-functioning switches on a brand new KMAC PCB I've just put together? I plugged it in to do a quick AquaTest when I saw that Esc, F8, F12, and Menu (87-key layout) don't work. First I thought--oh I forgot to solder the switches somehow, as it had never happened before where a switch would not register otherwise. Nope, all the joints are nice and shiny. I've replaced the Menu switch with 2 other switches as a test--still doesn't register. Next I looked at diodes--all look neatly SMD-soldered. I reflowed the Esc diode as best as I could, but that didn't help with Esc not registering.
It didn't register those keys "out of the box" so to say. Tried new firmware just now (Easy Keymapper), but that didn't fix anything :( Any ideas where to go from here? Faulty controller? What measurements to take?
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I'd check the joints again with a multimeter's continuity test. I'm notorious for making solder joints I think will work but are actually cold. And the continuity test is always the first test I use to check a board when I'm having issues like yours.
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I don't think solder joints for the switch pins have anything to do with it, as I've never had a cold joint to date, and I've soldered lots of keyboards. Plus I've tried 2 alternative switches, so that's 2 re-solderings for the non-working switches, and that didn't help. Testing now though.
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Test the controller on another PCB if you can. Worst case scenario, it works and you've got a bad PCB, or it doesn't work and you've got a bad controller.
Other than that, seems as though you've eliminated most of the possible causes.
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Might be the switches themselves somehow... Just reflowed all the joints again, and it did nothing. But I can actuate all but Menu with my multimeter by doing a continuity test on the switch pins. I guess maybe the leaf is not working properly on those switches.
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Might be the switches themselves somehow... Just reflowed all the joints again, and it did nothing. But I can actuate all but Menu with my multimeter by doing a continuity test on the switch pins. I guess maybe the leaf is not working properly on those switches.
Then it has to be the switches. Test them before soldering them in, and then again after.
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Might be the switches themselves somehow... Just reflowed all the joints again, and it did nothing. But I can actuate all but Menu with my multimeter by doing a continuity test on the switch pins. I guess maybe the leaf is not working properly on those switches.
I've had corrosion issues or odd leaf problems with single switches in the past. Just swapped out the switch for another one and it worked fine.
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Yeah, it's the switches :( I'm guessing the leaf parts got bent imperceptibly on these, as the switches were set to me in open housings, but most looked to have been okay (I discarded those with obviously bent leaves). Will replace discerningly now. Thanks all.
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All is well now, typing on this keyboard. Thanks.