Macintosh KTK-1086 VER 1.2 Microcontroller Replacement

Zh1nu

11 Oct 2021, 07:17

Hi there, first post on the Deskthority forum.
I recently bought a MacColby SE shell for restoration, and I'm currently working on the keyboard.
The keyboard is a KTK-1086 Ver 1.2, with unknown (i assume the alps clone) switches. However, it's missing the main controller that the keyboard would normally use.
Is there a way I can put in a teensy or something? I traced out a bit of the board but don't know where to go from here. The three choices I see are fully reverse-engineering the board, pulling off components I don't need and wiring in a teensy, or pulling off the PCB and just handwiring everything.
I do wish to get it so that ADB works on it since the Macintosh SE needs ADB.

Photos: https://imgur.com/a/pbJ3UjT

Thanks for the help!

John Doe

11 Oct 2021, 08:27

Since missing the controller, making an adapter is not a go anymore. Easiest way is to figure out the whole matrix and connect rows&cols to teensy and remap all keys with QMK. The components are not needed anymore either but you could leave em there or just remove them, its your preference. Reusing the components are also practical but you'll have to do deeper reverse engineering job for pcb and in this case you also need to modify bit of the source file(matrix.c I believe).

Wish help.

Zh1nu

11 Oct 2021, 08:39

Hi there,
Would finding the mask rom for the microcontroller be an option? This keyboard seems to have been used in a few 286-portables, and i've seen a few people find them on this website. If one would be kind enough to dump the rom and send it to me, I could reflash it and get a PS/2 version of the keyboard working.

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Muirium
µ

11 Oct 2021, 11:24

Zh1nu wrote:
11 Oct 2021, 08:39
This keyboard seems to have been used in a few 286-portables…
Sure it's this exact keyboard you're seeing elsewhere? The layout is a compact version of the IBM AT, which was very widely copied indeed.

What's your goal with this: to use the keyboard on a vintage ADB Mac exclusively? Or to have dual outputs: ADB + USB?

Zh1nu

12 Oct 2021, 07:42

Muirium wrote:
11 Oct 2021, 11:24
Zh1nu wrote:
11 Oct 2021, 08:39
This keyboard seems to have been used in a few 286-portables…
Sure it's this exact keyboard you're seeing elsewhere? The layout is a compact version of the IBM AT, which was very widely copied indeed.

What's your goal with this: to use the keyboard on a vintage ADB Mac exclusively? Or to have dual outputs: ADB + USB?
Yes, it's the exact keyboard from this page, or at least very similar.
wiki/Unitech_K959 (check KTK-1086 Ver 1.2 unkown branding)
The only thing that seems different are the keycaps.

I'd like this to be ADB only, but if both is only a minor job away then i'll do USB and ADB.

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Muirium
µ

12 Oct 2021, 12:38

I see what you mean…

Image
Image

As far as I know, no one has made a custom controller with ADB output. ADB's a pretty weird protocol. It supports daisy-chaining devices, and instead of 4 wires it combines signal and data on the same line to make it 3. Sneaky Woz designed it himself. As Apple stopped selling computers with ADB ports on them long ago, so there's no real demand to make it happen in custom controllers.

Converting *from* ADB to USB is a solved problem. But ADB output isn't one I can point you to. You can surely hook the board up to a custom controller (on a Teensy or similar) to make it output USB. But getting to ADB output is the bit where my knowledge ends.

Why is your controller chip missing, do you think? Maybe someone harvested it?

Zh1nu

13 Oct 2021, 01:55

Probably not. The thing I bought was a NOS MacColby SE case + keyboard found in the CEO's basement. He had also an extra keyboard for sale, and that was missing the controller. I assume when they finally got assembled they would install a specially programmed microcontroller to get it working. If it goes to USB or PS/2, I'm fine cause then I can use a converter to convert it to ADB.

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joebeazelman

13 Oct 2021, 04:55

I wouldn't attempt trying to implement a custom ADB controller for the keyboard. It's a nightmare to implement and even Apple got it wrong at least twice. It's the reason why some keyboards work well and others are a bit more finicky. The PCB matrix is already labeled for you and it will be a matter of simply harvesting a controller chip from another ADB keyboard. The ADB interface has 4 pins: power, ground, data and reset. Apple portables from the past up until today with the MacBooks, usually don't include the keyboard controller on the PCB. Instead, it breaks out the individual matrix lines out to a ribbon cable that plugs directly into the logic board. The header on your PCB appears to output ADB signals, instead of a matrix.

Your best bet is to find a cheap old Mac compatible keyboard and salvage its controller. You can get dirt cheap rubber dome ones for well under 20 dollars. Try to find one with a non-detachable keyboard as those are more likely to have the same or similar keyboard. If you're lucky, it should just be a drop in replacement, otherwise you'll have to make a adapter board to remap the pins. They are pretty easy to make by remapping the pins.

Zh1nu

13 Oct 2021, 06:49

The keyboard uses a P8049AH, which I don't think any Apple keyboards used. The header on the board is meant for PS/2, but when it was still used was probably hijacked to put out ADB. Also, the matrix is weird as hell (I mapped it out, check the Imgur link at the beginning of the post), and half of the rows go to a 74 chip. I'll check and see if the rubberdomes I have even have the right controller, but I doubt it.

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soyuz

13 Oct 2021, 14:32

Put teensy in, convert to USB, buy ADB Wombat which can convert USB keyboards to ADB.

Shocking that people in this thread have been talking like USB to ADB isn't a solved problem.

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Muirium
µ

13 Oct 2021, 14:36

Not shocking. Just news to me. Like I said: "as far as I know…" And sometimes I know shit! ;)

kelvinhall05

13 Oct 2021, 15:11

Muirium wrote:
13 Oct 2021, 14:36
Not shocking. Just news to me. Like I said: "as far as I know…" And sometimes I know shit! ;)
yeah but most of the time you don't lmao

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Muirium
µ

13 Oct 2021, 15:50

Exactly. Maybe I should have italicised shit there! :lol:

Anyway, if USB to ADB is doable now, then just go that route. USB the board and feed it through a USB > ADB converter. I'd still beware ADB's flaky foibles, though. I've had trouble with it just using authentic Apple hardware as well.

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