Author Topic: Keytronic Keyboard  (Read 739 times)

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Offline Bludude4

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Keytronic Keyboard
« on: Fri, 05 October 2018, 10:47:11 »
Yesterday I pulled a keyboard I've had in storage for at least 2 years out of my closet, and decided to unscrew the case. As it turns out, the board has KeyTronic switches. I think they're foam-and-foils, but I'm not 100% sure. What I AM sure of is that I really like how the keyboard types. I really like the action of the linear switches, and the feel of the spherical double-shot keycaps.  The keyboard has a sticker on the bottom saying it was manufactured in 1983.

204910-0
204912-1
204914-2
204916-3
204918-4
204920-5
204922-6
There's some gooey stuff stuck to the case, as shown in the photos below.
204924-7
204926-8
204928-9

I'd use goo-gone, but I'm not sure what that would do to the plastic of the case; I'm worried it might discolor it or make it brittle. Is goo-gone safe to use on these, or does anyone have an alternative recommendation for cleaning off this grey goo? Looks like an old adhesive of some sort, but I have no idea for certain.


ALSO

I know a few people on this forum have the necessary tools and know-how to reverse engineer this keyboard and program a microcontroller to convert this sucker to USB / PS/2...
Anyone wanna do it? I really don't care how long it takes and I'd pay for shipping and your time. Goes without saying that while you're doing so, you can take it as far apart as it can go, as well as taking as many pictures you like and posting them anywhere you like. Here's a video of the keyboard:



Cheers,

Bludude4
« Last Edit: Fri, 05 October 2018, 11:29:34 by Bludude4 »
All hail Hall Effect keyboards!
I'm a QFR Blues noob.
WASD keycaps are terrible.

Offline OldIsNew

  • Posts: 116
Re: Keytronic Keyboard
« Reply #1 on: Wed, 10 October 2018, 20:03:27 »
I like that board! Cool front legends on the keycaps too. At least to me,  it certainly looks like could be a vintage KeyTronic, but really have to remove a keycap to be sure.  If it is (like this board),

205216-0          205213-1

then it's not really that hard to convert - you can trace out the matrix from the pads with a simple multimeter, then use the multimeter to find the IC connections and wire to a Xwhatsit Model F to USB board. (I've seen that  the DMA common sense works well too but I don't have any personal experience with that one). The main issues I've found with the KeyTronic F&F boards are 1) capsense  is sensitive so often have to desolder many, if not all, of the onboard controller components,  and 2) the F&F is usually rotted and needs to be replaced. Both issues are tedious to deal with but not really difficult.

As far as the gunk on the board - I would be VERY carefully with most organic based solvents including Goof Off (or goo gone). Can really mess up plastics - and if the case is painted I've learned (from unfortunate personal experience) that even isopropyl alcohol can remove the paint. For plastic, or painted cases, I've found liquid laundry detergent, warm water and a brush seems to be the best approach.

Maybe you could post some pictures of the opened board?

EDIT:
For some reason I couldn't get your video to open when I first tried, but now it does -  and those are vintage KeyTronic F&F.  The red stained springs too - I don't know that's of any real significance but I like them ( BTW isopropanol will remove the red coloring).

« Last Edit: Wed, 10 October 2018, 20:30:36 by OldIsNew »

Offline ander

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Re: Keytronic Keyboard
« Reply #2 on: Thu, 11 October 2018, 06:10:32 »
That's a beauty, a real classic look. People pay hundreds of bucks for reproduction keys that look like that, and aren't even as well made. I hope you get it up and running.
“The cool thing about being famous is traveling. I've always wanted to travel across seas, like to Canada and stuff.”
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Offline Bludude4

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Re: Keytronic Keyboard
« Reply #3 on: Thu, 11 October 2018, 11:32:18 »
I like that board! Cool front legends on the keycaps too. At least to me,  it certainly looks like could be a vintage KeyTronic, but really have to remove a keycap to be sure.  If it is (like this board),

(Attachment Link)           (Attachment Link)

then it's not really that hard to convert - you can trace out the matrix from the pads with a simple multimeter, then use the multimeter to find the IC connections and wire to a Xwhatsit Model F to USB board. (I've seen that  the DMA common sense works well too but I don't have any personal experience with that one). The main issues I've found with the KeyTronic F&F boards are 1) capsense  is sensitive so often have to desolder many, if not all, of the onboard controller components,  and 2) the F&F is usually rotted and needs to be replaced. Both issues are tedious to deal with but not really difficult.

As far as the gunk on the board - I would be VERY carefully with most organic based solvents including Goof Off (or goo gone). Can really mess up plastics - and if the case is painted I've learned (from unfortunate personal experience) that even isopropyl alcohol can remove the paint. For plastic, or painted cases, I've found liquid laundry detergent, warm water and a brush seems to be the best approach.

Maybe you could post some pictures of the opened board?

EDIT:
For some reason I couldn't get your video to open when I first tried, but now it does -  and those are vintage KeyTronic F&F.  The red stained springs too - I don't know that's of any real significance but I like them ( BTW isopropanol will remove the red coloring).



So I would only need a multimeter to trace out the PCB, no oscilloscope required? Sweet! That shouldn't be too hard then.
I see that xwhatsit has a couple different controllers, one for beam springs, one for model Fs. So this is the part I'd need to buy, right?

https://oshpark.com/shared_projects/eTR858GJ

So I basically have no PCB rework experience...at all. I don't know what capsense is. (My guess is that's the name of the firmware for the xwhatsit controller?)
So... I'd have to desolder the SMD's on the PCB? All of them? Some of them? Which of them would I have to desolder? Would I have to wire up the contacts that the SMDs mount to, or just leave those circuits open after removing the SMDs?

I can open the board back up and post some pics of the PCB if that would help any.  I really don't know how to do this, so if there's a guide on tracing out a PCB for an xwhatsit microcontroller that exists, it'd be really great if I could get the link to it.

As far as the F&F rot, after watching Chyrosran's F&F board reviews, I'd like to keep the F&F switches...rotted. Apparently the keyfeel is mushy if the F&F is intact. Does the F&F rot make the switch not register anymore, leaving me no choice but to fix the F&F? Or will the key still actuate with the rotted F&F?

I will try the detergent, warm water and brush, and I'll post how it goes here.

Thanks for the help!

Cheers,

-Bludude4

That's a beauty, a real classic look. People pay hundreds of bucks for reproduction keys that look like that, and aren't even as well made. I hope you get it up and running.

Thanks, I really like how it looks too. It's a behemoth. The spherical key-top sculpting is really deep too, something I'll probably have to get used to, but I really like.  I seriously hope I get it up and running too.
« Last Edit: Thu, 11 October 2018, 11:35:02 by Bludude4 »
All hail Hall Effect keyboards!
I'm a QFR Blues noob.
WASD keycaps are terrible.

Offline OldIsNew

  • Posts: 116
Re: Keytronic Keyboard
« Reply #4 on: Thu, 11 October 2018, 21:45:53 »
The matrix of these boards is pretty easy to figure out using the continuity testing feature of a simple multimeter (technically you don't really need to know the individual rows/columns of every key with the Xwhatsit as long as you know you have identified all the rows and columns -  I just do the whole matrix to avoid missing anything). What I typically do is take a picture of the the front of the PCB (the large silver pads) and just start at the upper left corner holding one multimeter probe on the first pad and then tapping each others others in order checking for continuity and marking the rows and columns on the picture that way.  I personally usually label the columns by letters and the rows by number, but it doesn't really matter. Once that is done I will check each row/column for continuity with one of the IC legs and mark this down on the picture too (while holding one probe on the row/column pad you are checking, just have to run the other probe along the various IC legs until it registers).

Capsense just refers to the capacitive key sensing mechanism of the board. I've certainly found it's sensitive to stray currents. I have used the multimeter to check the various onboard components for connections with the row/column IC pads and only desoldered the ones that seem to be an issue but, more recently, I've taken to desoldering all the resistors, caps and ICs on the board to avoid having to go back later and deal with sensing problems. This is probably the riskiest part of the process since it is very possible to damage/lift  pads if not very careful. I am by no means an expert solderer. I practiced quite a bit on old broken electronics boards before working on my keyboards and so far (knock on wood) have not ruined anything. You can look up videos on how to solder/desolder on youtube too if you're not experienced.

I've also found that on boards with rotted foam and foil (all of the ones I've come across so far), the F&F has to be replaced to get a functioning board. I personally have not run into the "mushy" issue. Maybe I'm just not sensitive enough to detect it, but honestly I think the resistance/feel of the springs is much greater than the contribution of the foam (unless you deliberately choose a very stiff foam I suppose). I have been using an open cell polyurethane foam and really can't feel it. If you're using the Xwhatsit Model F to USB, then once the F&F is replaced (or not if you've gotten lucky) and you know which IC pads correspond to which row/column and have done the desoldering, then it's just a matter of soldering the row/column IC pads to the row/column pads of the Xwhatsit Model F to USB board (along with a ground). The Xwhatsit documentation includes the diagrams. You will also need to install the Xwhatsit Capsense Keyboard Utility (also on Xwhatsit's website). Then follow the instructions to set sensitivity and assign the keys. It took me a few read thoughs of the documentation, but it really is not complicated.