WTB - old controller parts from IBM model F XT

[nama]

Hi all,
Have you upgraded your IBM Model F to USB by cutting of the old controller, or happen to have the original controller parts spare (maybe from an old junker keyboard)?
I'm looking for the 8048 Microcontroller and a 8273565 Sense Amplifier as I want to get my Model F keyboard working with my original IBM PC.

Much much thanks in advance
Philip

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[Muirium]

Yes, I have a parted out XT, as we call them: the original keyboard for the 1981 IBM PC. Where are you located? I might be a bit far away, here in Scotland.

It's unusual for the controller itself to break. In the XT, the controller is inseparable from the main sense PCB that's sandwiched deep in the keyboard's inner guts. (Well, inseparable unless you cut real straight…)

I have the whole insides of the keyboard spare if you need them, minus the flippers and barrels which I harvested for a project.

[nama]

HI Muirium,
Much thanks for the reply.
My keyboard is presently in bits and I've been testing just the pcb (and the controller of course) seperate from any other components.
As far as I can tell I have an issue with the SA_CLOSED line, and I am unsure if that line is generated from the 8048 or the Sense Amplifier. You can read about all the testing I've done here:
https://forum.vcfed.org/index.php?threa ... e.1244310/

I've already found one bad cap which has been replaced, but unfortunately that didn't fix the problem.
I'll PM you.
Cheers

[Muirium]

I see from your link that you're in New Zealand, quite a ways away indeed! The legendary Xwhatsit—who made USB controllers for beamsprings then Model F was from New Zealand too. Amusingly, my main IBM's controller came straight from him (10 years ago) in the post from NZ!

Going by the thumbnail in your link, you are indeed working on an XT:



I've definitely got the bits you want, albeit half the world away.

[nama]

The other side of the world!
I wonder how much shipping would be? One thing in our favour is the package would be relatively thin and light, but you would certainly want it to be stiff. The last thing you'd want it it to be folded in half in transit!

[Muirium]

Okay, here's what I've got, fresh out of storage:

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Here's an incomplete set of XT caps. Do you need any? (Think I saw you mention you were short a few for one of your XT's over in your thread.)

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A closeup of the controller ICs. Note: this one is untested. Probably works but I've never used it, as I remember. It was bought from Cindy in Texas for flipper and barrel harvesting. I think my AT and Kishsaver have several of the absent caps, too.

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Here's the top/sense side of the PCB. It's currently still attached to the backplate. (Haven't found the right hex tool to take it off!) Together they weigh precisely 666g. I'll probably take it off for shipping, as it doesn't protect the controller anyway.

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Going through the bag of XT caps, I found these fellow IBM single-piece caps: but they're not XT. They're probably just my single-piece spares.

I've also got the spacebar stabiliser wire, if you need one of those. The big spacebar barrel/bar is obviously spare as well. Also got the top plate (and crumbly foam attached) but that's fair weighty excess unless you need it.

[Muirium]

Found the quarter inch hex driver: the PCB/controller alone is 124g. It'll bulk up a bit for safe shipping, though, so little extras should be free join the ride.

[nama]

Oh wow...look at you. Thank you very much. That's brilliant!
Regarding the metal back plate. I do have one, but it was very rusted up and I have sanded it back and painted it to prevent further spread of the oxidisation (see photo). I'm sure it'll be fine for reassembly, but if you could include the back plate and it wouldn't incur extra shipping fees, that would be wonderful. If not, then I hope the one I've painted will do a decent job.
As for keys, you are correct, I am missing a couple. Specifically the F8 key and the ALT key. Again, if you could include those...brilliant and thanks!

Cheers again
Philip

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[Muirium]

The F8’s yours. The Alt is too small for an XT though.



Think it’s AT size: 1.5 units. It would have gaps on both sides on an XT. What I can do is send you the XT sized Caps Lock though, which wouldn’t be perfect but would fill the space and more or less look the part. Think Alt and Caps Lock are the same size on XT. But it’s late here so better double check another day.

Shipping will be interesting. Could well be costly with or without the plate. I’ll look into it.

[nama]

Oh Yeah!!! The Caps Lock key will work...good idea.
Once you have an idea of shipping cost, please fire through a PM.
Again...much appreciated

[nama]

Quick question. Did you keyboard have a clear mylar sheet between the metal plate the the PCB. I've seen some videos where they do and some where they don't. I could have sworn mine did, but I can't find it! As the keyboard has been apart for some time now, I've either put it somewhere "safe" and forgotten where, or I'm just remembering incorrectly from having seen to many YouTube vids...

[Muirium]

Yeah, I think I've seen those sheets in tear-downs, too, but haven't encountered one in the various Model Fs I've been inside. If that board had one, I'd have put it back in for safe keeping. The best place to store things is in situ, whenever possible.

As usual, finding a good box is the hard part. I'll get back to you on quotes.

[nama]

ok, maybe I'm just remembering wrong. It's unlike me not to keep everything together, which also makes me question my memory. Cheers

[Muirium]

I found a good box, btw. Will pack it up tomorrow and get you some quotes. (With and without the heavy plate.)

PCB, backplate, and F8 and Caps Lock caps, right?

[nama]

Yes, perfect.
It's actually the F9 key I need, but it looks like you don't have that from looking at your photos, thats why I said the F8.
Thank you!

[Muirium]

Your XT will look perfect… on first glance.

Anyway, glad they'll find a new home. I’m always loathe to throw spare parts away, in case someone (usually just future me) needs them.

[nama]

Yeah...In my opinion you did great!!!!
Agree. Unless you point it out, or use the keyboard for any time, you'll probably never notice.

[Muirium]

The bits are on their way. Good luck with the project!