Author Topic: Using "broken" switch's housings with new stems  (Read 1785 times)

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Offline Karura

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Using "broken" switch's housings with new stems
« on: Sun, 01 March 2015, 03:32:03 »
Hello, I was hoping to hear some advice for my project.

A while back, I acquired a Das Keyboard II (G80-3000) which came with PCB-mounted MX Blue switches.

Problem? Maybe 5 of the switches do not "click", and over 60% of the keyboard's keys do not register at all.

I do not know whether they don't work because the PCB has been damaged, or if it is the actual switches that are damaged, but when I plug the keyboard into the computer, it senses the keyboard, and some of the keys register.

Now, fast foward to a few months from now, I will be assembling a Leeku 3000 PCB to replace and upgrade the one in the Das Keyboard II.

I want to use WYSE vintage black switches, which have PLATE-mounted housings.

Would it be possible to harvest the PCB-mounted switch housing from the "broken" switches from the broken Das Keyboard II PCB?

Would there be a problem with the contact points or something that is causing the keyboard to not work?
Potentially, what are the chances of the housing just not working?

I hope someone has experience with this, and can give me their insight  :thumb:

Cheers
« Last Edit: Sun, 01 March 2015, 03:34:34 by Karura »

"Remember boys, raccoon cold... don't worry, raccoon will find cave." -Sent

Offline suicidal_orange

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Re: Using "broken" switch's housings with new stems
« Reply #1 on: Sun, 01 March 2015, 04:05:03 »
Switches are rated for millions of presses so unless someone opened them up badly and snapped the stems or spilt fizzy drink in them it's unlikely to be a broken switch.  The lack of click is a different problem as it's to do with the stem rather than the switch, if you open them up you might be able to fix them (I have no experience with these)

A cheap multimeter can confirm whether the switch is broken (continuity mode - it will beep when connected to the two pins while the switch is pressed) so it's probably worth buying/borrowing one to test.  Or better yet borrow the owner too - one of you can hold the switch the other the probes, would be much quicker.

Assuming the non-working keys are all in blocks (e.g. 1qaz or tab qwer) they are connected in the switch matrix and that would mean it's a controller/circuit failure which is much more likely, but with that many not working it would be hard to know.

I say go for it.  If you've had the Das from new I'd think the switches are fine, if not find a multimeter and test them to be sure :)
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Offline Dihedral

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Re: Using "broken" switch's housings with new stems
« Reply #2 on: Sun, 01 March 2015, 04:37:39 »
Yes, you can harvest the switch housing. The only difference is that the pcb mount switches have two extra stabilising pegs. They should still work fine. If not, you can just grind off the pegs.

Offline IvanIvanovich

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Re: Using "broken" switch's housings with new stems
« Reply #3 on: Sun, 01 March 2015, 09:22:13 »
Well... when a switch fails 98% of the time it's because the contact points are faulty. Putting in a new stem won't help such cases.
As for G80, especially those that have the separate controller PCB when many keys are not working it's usually because the connection to the controller is bad. Some models they used really awful kind of ribbon connector which has stiff hard wire wrapped in paper tape looking thing. Often the wires crack inside. I've fixed quite a few by replacing that with softer wire that isn't prone to cracking in that manner.

Offline Karura

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Re: Using "broken" switch's housings with new stems
« Reply #4 on: Mon, 02 March 2015, 01:38:54 »
Thanks for all the replies. I will go out to buy a multimeter.

Is it possible to just test the switches while they are still soldered in the PCB? I don't want to de-solder them to test, if I don't have to.

Also, to be specific, I am trying to source pcb-mounted housings for my vintage black stems, which were originally housed in plate-mounted housings.

"Remember boys, raccoon cold... don't worry, raccoon will find cave." -Sent

Offline suicidal_orange

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Re: Using "broken" switch's housings with new stems
« Reply #5 on: Mon, 02 March 2015, 02:10:52 »
Yes, testing in the old board will work - if you couldn't tell if the switch is pressed or not nor could the controller, so no keyboard could work :))

You will want to borrow a friend in this case, holding two probes on one side of the board while locating and pressing the right switch on the other is not at all easy.
120/100g linear Zealio R1  
GMK Hyperfuse
'Split everything' perfection  
MX Clear
SA Hack'd by Geeks     
EasyAVR mod

Offline IvanIvanovich

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Re: Using "broken" switch's housings with new stems
« Reply #6 on: Mon, 02 March 2015, 09:46:47 »
It's kind of the opposite of testing the switch... but it can be helpful to determine if it's switch problem or the pcb/controller. While still connected to PC open the case so you have access to the bottom of the PCB. Open up aqua key test or similar. Use small metal something to bridge the 2 switch legs. If it sends a character when it does not if you press the switch, more than likely the contacts in the switch are damaged and it's not worth saving that switch.

If that proves inconclusive you can make ghetto cont. tester with a 3v battery and led following the concept...

If the switch is good the led lights up. Simple.
« Last Edit: Mon, 02 March 2015, 09:48:22 by IvanIvanovich »