Upgrading a Chicony KB-5981

[baked_cake]

I have a chicony keyboard with momentary blue alps switches. I love the switches but the processor is terrible. It cant perform certain key combos. I am interested in upgrading it to a more modern processor and an ps/2 plug.

The chip is a DIP 40, here is the information on it:

Deawoo Appian GC
Chicony Ver-L 105-08049-250
DMC80C49-187A
Intel 9739G

Can anyone point me in the right direction?

[Touch_It]

As far as a ps2 cable goes you just need to do a cable swap. I replaced my cord with a ps2 from an old compaq rubber dome. An at to ps2 adapter would do the exact same thing. As far as the processor goes soarers converter would likely do the trick as I believe the controller is limiting it but I'm not smart enough to know for sure. On another note, glad to see someone else who has one of these. They are pretty rare. Sadly some of my switches have stopped working. I need to play doctor sometime.

[baked_cake]

Yea I tried taking the scroll lock switch part just to see whats in it. I took my time on it too and the thing has never been the same, doesn't click anymore, those switches are pretty complex. I will look into soarers converter, thanks for the input.

[Hak Foo]

It's probably not directly the "processor"-- the controller.

Some keyboards have one diode wired in series with each switch. This allows any combination of keys to be sensed correctly.

Many left out the diodes. Saves money, makes the layout simpler in some situations. In that design, it becomes ambiguous trying to sense certain combinations of 3 or more keys. The controller will usually bail out and refuse to register them.

They try to design the layout of the board so that those ambiguous combinations won't be popular combinations to hit together, but sometimes fail to anticipate your needs.

No replacement controller or adapter will directly solve that problem. You may be able to rewire the board to add diodes, then add a new controller that's aware the board has diodes, but that's likely to be a project basically on the scope of "let's just salvage the switches and keycaps and build a whole new keyboard around them."

Your best bet might be to find another board that has ALPS-style switches and diodes (usually labelled N-key rollover), and get someone to do a switch transplant.

[baked_cake]

I do see some parts on the board that have diode indicators, but have been bridged by a solid wire instead. If I wanted to gain full access to the board i would have to de-solder everything in order to the pull the metal mounting plate away from it as well. You might be right about transplanting the switches...

I haven't tested it fully, but the one thing that irks me is not being able to use the up and left arrow at the same time.

[jacobolus]

momentary blue alps switches.

Pedantic side-note: these switches were made by SMK, and have nothing to do with Alps beyond the keycap mount. They get called “Monterey” around here because they were used in a few keyboards made by Monterey, a keyboard OEM. The Deskthority wiki calls them “SMK second generation” switches, in particular these are the clicky Alps-mount variety of SMK second generation switches. It’s kind of a lame name, but I don’t think anyone has any old SMK catalogs to find out what they actually called them, so it’ll have to do.

It's probably not directly the "processor"-- the controller.Your best bet might be to find another board that has ALPS-style switches and diodes (usually labelled N-key rollover), and get someone to do a switch transplant.

Note, this isn’t going to help anyone, since neither the plate nor PCB from an Alps switch keyboard will be compatible with these switches.

Anyway, back to your topic: to get the best results, you can desolder all the switches and throw away the PCB, and then direct wire a diode matrix and hook it up to a new microcontroller board (e.g. a Teensy 2.0). Then you’ll get n-key rollover, programmability, USB output, etc. That’s a somewhat complicated and time consuming project though.

[jacobolus]

By the way, once you figure out how the switches are constructed, they’re not all that bad to take apart and put back together (at least when they’ve been desoldered and are loose). Not quite as easy as MX or Alps switches, but better than several other types of switches.

[baked_cake]

jacobolus: This sounds like the most ideal route I can take. Can you point me to any information for the wiring diagram I should use?

[Findecanor]

momentary blue alps switches.

Pedantic side-note: these switches were made by SMK, and have nothing to do with Alps beyond the keycap mount.

Just to be sure, the switches do look like this don't they? (never mind which keyboard case they are in)

[Muirium]

Here's a couple of good guides:

Homemade hand-wired keyboard:
http://deskthority.net/workshop-f7/brow ... t6050.html

Hand-wired Apple M0110 conversion:
http://deskthority.net/workshop-f7/the- ... t1067.html

Beware: this is a *lot* of fiddly, detailed, time consuming work. I'd keep the stock PCB if you can. Are all of those bridged diode locations accessible? Is there one for every switch? And is the controller (the chip that drives the keyboard and sends output to the computer) on a separate PCB? If all answers are yes, you are lucky. Otherwise, could well be that handwiring is your only option.

[jacobolus]

jacobolus: This sounds like the most ideal route I can take. Can you point me to any information for the wiring diagram I should use?

Check out these threads:
http://deskthority.net/workshop-f7/the- ... t1067.html
http://deskthority.net/workshop-f7/brow ... t6050.html
http://deskthority.net/workshop-f7/tuto ... t7431.html

There are a few others floating around here and geekhack, but those three should give you enough ideas to chew on for a while.

[Daniel Beardsmore]

A switch confirmation (pictures are better) would give us our first date for these (1997) and the first high-water mark for SMK 2nd gen switches.

[baked_cake]

Here are some pictures of the keyboard.

http://imgur.com/AXmEIa3,wdJ9Tue,1UC0yl ... ot,Yabs2qd

As you can tell my camera is a giant piece of crab but I did manage to get it to display the correct color. I slightly mangled my scroll lock on the second attempt but the upside is i finally figured out how to properly take these things apart and reassemble them.

Thanks for the links, I feel confident enough to begin the hardware modification now, or at least ill have plenty of time to figure out the rest of it as I go

[Daniel Beardsmore]

You got those switches apart while still soldered in place?

I want to see the ones that jacobolus thinks are harder to reassemble than SMK switches. SMK are the only ones where I've actually given up and admitted defeat.

[baked_cake]

I can pull the tops of but it is pretty tricky. I have to use a pair of shims to wedge the inner snaps apart then pry up the snaps that connect the top of the switch to the mounting plate. If i try to desolder it with the top off the whole thing pretty much comes apart and the bottom half is free.

It's next to impossible to put the switch back together when its not soldered to the board, lesson learned.

[Daniel Beardsmore]

That's the opposite of typical Alps clones, as they're a nightmare to reassemble in-place, but really easy to assemble when de-soldered. I couldn't get an SMK switch apart while soldered in, but I can see that it it would at least keep the contacts steady. They're strange switches.

[baked_cake]

It looks like I was mistaken, they can be reassembled while desoldered from the board. I had to hold the upper half of the switch upside down and fit in all the metal contacts in a certain order and once everything was lined up absolutely perfect the thing snapped together with ease. I haven't tested it with an ohmmeter yet to see if I got it right but I feel pretty good about it.

update: it works

My scroll lock key on the other hand, will require new metal contacts :/

[jacobolus]

I want to see the ones that jacobolus thinks are harder to reassemble than SMK switches. SMK are the only ones where I've actually given up and admitted defeat.

Well, I guess the main harder ones are switches with the housing held together by glue. I find SMK switches aren’t too bad as long as you put the parts back in in the right order. I’m on vacation and don’t have any here with me, but when I get back home in a couple weeks I can try to describe my method.

[baked_cake]

http://imgur.com/RwrflBv,yZnpZ2N Tadaaaa

For anyone who is planning on doing this project, you have to pull the switches off the metal plate before you can remove the PCB (after you desolder them). I also had to shift a pair of capacitors out of the way and wedge up a little on the metal where it caught on the processor. Then the PCB can slide out of a couple metal brackets that secure it to the metal plate.

Part # on the board is:

001-05981-K02
02V0 9737

Now I sit and wait a couple days for some diodes to arrive -_- I guess I can look into some replacement parts for Mr. scroll lock.

[Daniel Beardsmore]

OK, all three of my loose SMK 2nd gen switches work again. One of them has to be almost fully bottomed out to register — IIRC I bent the actuator leaf, and I'm not going to take another one apart again to figure out what shape it should be. They all feel normal though. Silly things.

[Touch_It]

Off topic I know, but sadly I have a dead switch on mine. Next step will be to open, but I moved the switch to the pause/break key and don't feel like going through the effort atm.

[baked_cake]

Not too pretty but it works so far. Had to take some paint thinner to the ends of the diodes where they had tape gum on them. I was about 5 diodes short so I just pulled them off the old PCB hehe. Solid Strand telephone/thermostat wire works perfectly for the vertical rows as well.

[Daniel Beardsmore]

Wait, the KB-5981 has NKRO? I didn't realise.

[baked_cake]

Daniel, It does not, or at least I'm not even going to bother testing if the original chip could(the PCB was probly the main problem, I couldn't even use the up and left arrow at the same time). However now that i think about it, that chip is a dip 40, it certainly has enough inputs :/

Update: Well I'm totally stalled lol. I went and got a teensy 3.1 thinking I'm the best guy there ever was, only to realize most of the keyboard guides built their code on the teensy 2.0. Since I am pretty newb at programming, I'm either stuck learning how to do it myself with Arduino, or take the damn thing back for a teensy 2.0. Can't decide :/

[baked_cake]

I got it working! Ordered a teensy++ 2.0 and hashed out some of the Ergodox code for my layout, and some of the stuff that needed to be updated for the teensy++ 2.0 (he doesn't have any options in there for other controllers, yet) and everything but the numpad is just about sorted out. I'm thinking about making a post in the projects forum that would include the software modifications I had to do, Since that seems to be the main thing that doesn't seem to be well documented in some of the guides on here. I have to admit tho, the Ergodox code is documented very well, so much that I was able to figure most of it out by myself, and some help from the PJRC website.

[BussoV6]

Interesting. I have a KB-5181 I might do this modification to. Good work!

[baked_cake]

Thanks! I'm a n00b at soldering and code, so actually getting this thing to work was very satisfying.