[Futaba Sealed Linear] Execuitive Periphial Systems KB-A3

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zrrion

18 Feb 2020, 05:43

Here we have a keyboard from the far off year of 4188.
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The future is looking bright for the aesthetic direction of keyboards.
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The box has a different model number on it, so this may be a different keyboard that the box is for. Hard to say though, the building is for a SAT prep place and I don't think they know anything about this time traveling keyboard.
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This connector on the end appears to be intended to socket into an existing IC socket, rather than any sort of external plug. I suspect this was intended to be used as an external keyboard for a computer with an integrated keyboard, there appears to be an unpopulated socket which I suspect was to connect the integrated keyboard's cable that way you wouldn't loose functionality.
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And underneath a hinged lid we have storage for cartridges and F-key overlays. My best guess is that the cartridge can store macros for various programs with the overlays being used to label the otherwise blank keys. This is strictly conjecture, but if this isn't what is going on here I have no idea what it could be.
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Getting to the caps, some of these appear to be compatible with fujitsu leave spring. I don't have any to confirm but there aren't really any other reasons to make your caps like this. They are all very thick, even the ones without inserts.
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The insert came out of one when removing it but I didn't take a picture of the insert somehow.
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and comparing it to another cap I found on a futaba board, the mount on each cap look like they were made in a similar manner although the profiles are not the same.
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And we get to the switches, they are definitely futaba but not a kind I am aware of. Internally they work the same as MD just with a different housing. I suspect that the slider is the same but I do not have loose MD switches to test with. The plastic of the housing is the same as other futaba switches I have and the colour of the bottom housing is similar to bottom housings I have seen posted. the legs screw in like MD as well, but on these switches the bottom housing is glued in for some ungodly reason and there is a jumper built in to all the switches. Since there are no clips for plate mounting these this is likely to make PCB mounting easier.
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The black switches are toggle switches which this board uses for the program key and the cap lock key. Despite one white switch being down that is not a toggle switch, it sticks down like that. Inside the slider there is a rubber piece that sits atop the spring. I suspect this serves as a dampener when the rod in the bottom housing that the spring sits on hits the slider. I believe what is causing this switch to stick is the rubber has shrunk a little and is allowing the slider to depress further into the switch than intended and the stiffness of the contact leaf is pressing horizontally on the slider in a way that, combined with any dust that has gotten into the switch, is preventing the slider from returning.
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and here we have a spacebar stabilizer. Interestingly enough it has four legs, just like the switches, and indeed it uses the same bottom housing, jumper, and screw in legs as the switches do. Hey, if it works...
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After marring a switch breaking the glue that holds it together we can see the complicated contact assembly of a futaba switch. This is the only switch I have ever heard of that is both glued and screwed together. If you have the option, just get MD, its the same feel and can be cleaned without destroying the switch.
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I do apologize for not getting more and nicer pictures of the board, but the assholes who built it glued all of the screws in and filled the heads with glue as well. There were a ton of screws holding the whole thing together and almost every screw got stripped trying to get it out, the PCB was damaged, and the entire thing was pretty cheaply made to begin with so I didn't reassemble after all was said and done. The board was a looker, but was built by someone who really didn't want it to be take apart. All of the pics of the board before disassembly are from the listing. I was planning to clean the thing up and convert it, but the switches and the board were both glued and screwed together in a way that makes non-destructive disassembly impossible. Maybe down the road I will make a metal back plate and some mounting brackets and stick a plate and some decent switches into this thing, but until then I guess i have some neat but disappointing switches and a bunch of ridiculously thick caps.
Last edited by zrrion on 19 Feb 2020, 06:56, edited 3 times in total.

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Chyros

18 Feb 2020, 09:30

Very interesting write-up, thanks! :)

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PlacaFromHell

19 Feb 2020, 03:26

That's the Futaba sealed linear switch. I would love to see this keyboard working with good switches and not that piece of stiff crap. What do you want to do with the internals? Would be nice to know if I ever want to do the same with my Televideo keyboard in the same situation.

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zrrion

19 Feb 2020, 07:06

I have considered modifying the top case to allow for a top-mount switch plate or possibly making a bottom plate with mounting brackets to allow for a bottom-mount switch plate. If I did that I could put whatever switch I wanted into the board but I am not sure what the best candidate would be. I would want to keep the same caps and so far the only switches i have that are compatible, besides other futaba switches, are Cherry M9. I suspect there are a ton of switches that would work, but I don't have any many examples to try.

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PlacaFromHell

19 Feb 2020, 09:39

Alps SKCC's, SKFF's, SMK vintage linears and some other stuff is compatible. You can also use 3D-printed keycap lifters like the ones used in reproduction Commodores with Cherry switches.

User avatar
zrrion

19 Feb 2020, 17:19

Short SKCC wasn't fitting when I tried but tall SKCC fits in the keys with inserts at least. I don't have any SKFF, but I would very much like to get some in the future. I want to avoid using adapters if I can though, especially MX>vintage adapters as it feels wrong to use modern switches when there are perfectly fine hint options.

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JP!

20 Feb 2020, 16:50

Rad looking keyboard and nice write up.

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