Author Topic: IBM Model M - Keyboard keeps automatically typing on its own  (Read 1011 times)

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Offline venturieffect

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IBM Model M - Keyboard keeps automatically typing on its own
« on: Fri, 08 January 2021, 15:21:44 »
Hi, I just restored an old IBM model M that was being thrown away at my office (I was blessed that day).

I bought this ps2/usb converter: Link and tried to attach it to my pc (windows 10)

The keyboard doesn't work properly: the input is sent like the keys are kept pressed down (so instead of "a" i get "aaaaaaaaaaaaaaaaaaa..." indefinitely). I tried to remove some keycaps an press the spring with a stick but the issue remains, so I don't think is mechanical.

Did i miss something or it's broken?



here's the gut shot:





Any pointer on how to troubleshoot this would be much appreciated



edit: after some digging. I found the adapter is recognized both to windows and linux as a barcode reader . maybe It's the adapter which is not correct
« Last Edit: Fri, 08 January 2021, 19:03:38 by venturieffect »

Offline funkmon

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Re: IBM Model M - Keyboard keeps automatically typing on its own
« Reply #1 on: Fri, 08 January 2021, 21:41:04 »
Huh. I've used that PS/2 adapter and it's fine. It might be worth returning and getting a new one, but I'm not sure. Try asking on deskthority or reddit.com/r/modelm, maybe some people there have had this happen.

I have had this happen with I believe a Model F when the key wasn't seated correctly, but iirc, it's because on a Model F the key is basically stuck open when the key is off, but the Model M doesn't work like that.

Offline venturieffect

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Re: IBM Model M - Keyboard keeps automatically typing on its own
« Reply #2 on: Sat, 09 January 2021, 07:10:30 »
Thanks I will do. It seems the issue happens with all keys indiscriminately

Offline funkmon

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Re: IBM Model M - Keyboard keeps automatically typing on its own
« Reply #3 on: Sat, 09 January 2021, 20:22:48 »
Thanks I will do. It seems the issue happens with all keys indiscriminately

Yeah, then I think the thing isn't sending a close command. You got a bad copy of the adapter. Try to get a replacement.

Offline venturieffect

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Re: IBM Model M - Keyboard keeps automatically typing on its own
« Reply #4 on: Sun, 10 January 2021, 11:40:28 »
After some discussion over reddit r/modelm it turns out my keyboard is a terminal keyboard, not natively for a PC (and it's most probable since it was a discard from my old office IT department supplies).
To get this keyboard to work i will need a Soarer's Converter or similar since most keyboards works with scancode 1 or 2 but terminal keyboards work over scancode 3 (or at least this is what i understand)

Offline funkmon

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Re: IBM Model M - Keyboard keeps automatically typing on its own
« Reply #5 on: Tue, 12 January 2021, 20:55:49 »
Maybe, but that shouldn't cause the issue you're seeing. I don't think you need a soarer's converter. Try to get another copy of the adapter first.

Online yui

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Re: IBM Model M - Keyboard keeps automatically typing on its own
« Reply #6 on: Wed, 13 January 2021, 06:10:01 »
3 things could be happening:
1 - you got a terminal board as code page 3 never sends break codes, you will have that is a page 2 adapter (although usually those are ISO, 122% and with a RJ11 plug, although exceptions are common in the world of M)
2 - the M is crashing the adapter, i had that happen to mine, depending on the adapters it will either happen on every keys, every so often or never
3 - either one is dead, although given your symptoms i would not actually bet on that

and barcode readers are just automatic keyboards, i work at IT and i have keyboards recognized by windows as barcode readers and barcode readers and RFID readers recognized as keyboards, no need to read to far into that.
as far as those adapters i had one crashing randomly on my M so they may be a tiny bit random, i had really good luck with tiny dual ports blue ones on ebay and model Ms.

TL;DR: i do agree with Reddit on this one, although if you could get your hands on a cheap/free rubber dome PS/2 kb to make sure it is not the adapter it could also be a good idea
vi vi vi - the roman number of the beast (Plan9 fortune)