IBM Terminal M cleanup and conversion

dotdash · 05 Feb 2019, 21:58

Came across an early 1992 Model M from a decommissioned AIX box. Has the ethernet type plug and no LEDs. Wanted to make this completely reversible, so I decided to pull the original cord and wire a teensy with Soarer's to a connector. The teensy then plugs into the original controller and the usb runs to a F socket where the cord exited the case. Not wanting to drill the case for LEDs, I decided to try under-key mounted LEDs run from the Soarer's.

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They keyboard was filthy, but not heavily used. The rivets were in good shape.

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I found a suitable connector in my box of old pc parts and moved wires to match the color scheme. I had some 3mm LEDs lying around. I ran one leg to a 500 ohm resistor, then the teensy, and the other leg I grounded on the existing case screw.

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Everything worked fine, but the LEDs were clumsy to run and make the case fit poorly. They looked ok when lit. I've ordered some chip type SMD LEDs to play with, which will hopefully fit and look better.

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The fit was a little sloppy, but I like the mini usb socket. I got a spare cord support bracket from Unicomp when I ordered replacement keys, so I didn't have to hack the stock one.

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fohat · 06 Feb 2019, 00:16

Great work with the NumLock light!

I just wish I knew how to make the light come ON when NumLock was OFF, since I never want it off and need to know when that happens!

dotdash · 06 Feb 2019, 17:43

fohat wrote: 06 Feb 2019, 00:16 Great work with the NumLock light!

I just wish I knew how to make the light come ON when NumLock was OFF, since I never want it off and need to know when that happens!

I would think that would be doable with modifications to the controller firmware. I've only used Soarer's, but perhaps you could compile a custom version of TMK with the LED behavior reversed.

zrrion · 06 Feb 2019, 19:38

You could also use some transistors and make an inverter which would do it without code. Code is easier but soarers is closed source so it isn't an option.

JP! · 06 Feb 2019, 20:31

zrrion wrote: 06 Feb 2019, 19:38 You could also use some transistors and make an inverter which would do it without code. Code is easier but soarers is closed source so it isn't an option.

Indeed, closed source but there was another member who did modify Soarers to reverse the key press logic needed to make a Model F Xwhatsit work with a beamspring Displaywriter keyboard.

Muirium · 06 Feb 2019, 21:00

Wait, what? Soarer’s code running on an Xwhatsit?

I remember the Soarer reverse engineer. He didn’t have the cheeky balls to publish his code, which was a shame but his call in the end. Soarer wasn’t ever going to go after him, but that’s the dubious grey area of IP abandonment.

I don’t get how it would run on Xwhatsit’s hardware, though. Besides, Xwhatsit’s controller was open source (far as I recall) and so seems likely to be what was modded.

JP! · 06 Feb 2019, 21:17

Muirium wrote: 06 Feb 2019, 21:00 Wait, what? Soarer’s code running on an Xwhatsit?

I remember the Soarer reverse engineer. He didn’t have the cheeky balls to publish his code, which was a shame but his call in the end. Soarer wasn’t ever going to go after him, but that’s the dubious grey area of IP abandonment.

I don’t get how it would run on Xwhatsit’s hardware, though. Besides, Xwhatsit’s controller was open source (far as I recall) and so seems likely to be what was modded.

Oops! Not Xwhatsit. Sorry I was getting things confused. Supposedly Arakula reverse engineered the hex file into more human readable C code but it could not be released since no one was able get in touch with Soarer.