Alps Cream Damped - resistance different depending on 'angle'

robo

07 Aug 2017, 01:50

As you all probably know by now from my many recent threads (:P) I just got an Apple Extended Keyboard II, my first Alps board since I last used a similar board in the late 90's.

The keyboard is extremely clean and appears to have been used minimally if at all. Mfg data is May 1991, made in the USA, and it has Alps SKCM Cream damped switches.I disassembled it for cleaning and some PCB mods, and it was almost dust free inside. I opened a couple switches and they also looked super clean.

And yet, the key switch action is not all that smooth. In particular, the switches seem very sensitive to where on the keycap you press. If you press in the very center, it's pretty smooth, but if you press towards the corner of a normal sized key, there's noticeably more 'sticking'. It's as if pushing on the keystem at an angle results in friction between the slider and housing.

Is this normal for Alps? On my Model M and Cherry Brown boards, the resistance is more or less the same wherever you press. I've heard that lube is not really recommended for Alps but it almost seems like these switches need it?

Thanks,

Robo

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Chyros

07 Aug 2017, 07:45

This is known as "binding". It's pretty common on dirty or heavily used Alps boards; it shouldn't happen in good-condition ones. Unfortunately, this sometimes includes boards that appear to be pristine :/ . I have one or two such boards myself, extremely disappointing.

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infodroid

07 Aug 2017, 10:40

Can this be fixed by applying an appropriate lubricant to the sliders? Or is swapping out the switch the only solution?

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seebart
Offtopicthority Instigator

07 Aug 2017, 10:44

infodroid wrote: Can this be fixed by applying an appropriate lubricant to the sliders?
No, it cannnot be fixed. Lube is simply "damage control". It may feel less horrible after PTFE lube.
infodroid wrote: Or is swapping out the switch the only solution?
It's the best solution if you have unworn & clean switches.

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balotz

07 Aug 2017, 13:59

robo wrote: As you all probably know by now from my many recent threads (:P) I just got an Apple Extended Keyboard II, my first Alps board since I last used a similar board in the late 90's.

The keyboard is extremely clean and appears to have been used minimally if at all. Mfg data is May 1991, made in the USA, and it has Alps SKCM Cream damped switches.I disassembled it for cleaning and some PCB mods, and it was almost dust free inside. I opened a couple switches and they also looked super clean.

And yet, the key switch action is not all that smooth. In particular, the switches seem very sensitive to where on the keycap you press. If you press in the very center, it's pretty smooth, but if you press towards the corner of a normal sized key, there's noticeably more 'sticking'. It's as if pushing on the keystem at an angle results in friction between the slider and housing.

Is this normal for Alps? On my Model M and Cherry Brown boards, the resistance is more or less the same wherever you press. I've heard that lube is not really recommended for Alps but it almost seems like these switches need it?

Thanks,

Robo
I have a number of boards with damped switches (cream and white), and have noticed this as well. The board I'm using now is pristine but still exhibits the increased friction on off centre presses. I can only assume this has something to do with the design of the slider, given that it contains the rubber dampers.

It's different from the horribly unpleasant binding you get with worn alps though.

robo

07 Aug 2017, 16:42

Is it possible (and reversible) to remove the rubber dampers? I could definitely see 26 year old rubber exhibiting different properties than when new, and maybe contributing to the sticking.

I wouldn't describe the sensation as 'horribly unpleasant', so I'm hoping it's something to do with the dampers, and not that the switches overall have mysteriously 'gone bad'...

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balotz

07 Aug 2017, 19:32

robo wrote: Is it possible (and reversible) to remove the rubber dampers? I could definitely see 26 year old rubber exhibiting different properties than when new, and maybe contributing to the sticking.

I wouldn't describe the sensation as 'horribly unpleasant', so I'm hoping it's something to do with the dampers, and not that the switches overall have mysteriously 'gone bad'...
You could try swapping in a slider from another alps switch?

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infodroid

07 Aug 2017, 23:17

The Matias Quiet Click uses dampers too. Not sure whether they are manufactured to the same spec, but they might be a good source of pristine dampers.

Here is a comparison photo from the wiki:

Image

Left: Matias QC, Right: Alps Cream Damped

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balotz

07 Aug 2017, 23:26

I just tried swapping a damped alps slider into an orange alps switch, and it did not exhibit the binding. It's probably not only the slider but the design of the housing.

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Wingklip

08 Aug 2017, 02:26

Likely the coefficient of friction on the housing being pretty high, what material is it made of? I heard it was abs but the color of the switch top seems to have some wierd swirls on it

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