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geekhack Community => Keyboards => Topic started by: Fallen_Angel72 on Sat, 29 May 2021, 15:01:35

Title: IBM model F XT component identification
Post by: Fallen_Angel72 on Sat, 29 May 2021, 15:01:35

Hello all, I am new to the forum, my apologies if this is posted in the wrong location, or if my question has already been answered (I am unable to find it on the site). I am in the process of restoring a fairly pristine IBM model F XT keyboard. It is not functioning (I'm using the appropriate converter, tracings and cable are fine), and I suspect there is a faulty component on the controller PCB. I am not skilled in identifying these vintage components, and am hoping someone can help me out, because I suspect I have found the problem (although it's likely that I'm just ignorant!). I have identified and successfully tested the other components, it's just this one that has me confused. Please see the attached image.

Description: A red, plastic, cylindrical component with the following numerical markings:
123
85 01
492
402

Title: Re: IBM model F XT component identification
Post by: Fallen_Angel72 on Sat, 29 May 2021, 15:04:37

Thanks a ton for any assistance!

Title: Re: IBM model F XT component identification
Post by: hasu on Thu, 03 June 2021, 23:11:36

You can find circuit schematics of the keyboard on bitsavers.org or kbdbabel.org.

http://www.kbdbabel.org/schematic/kbdbabel_doc_ibmpc_kbd.pdf
https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-XT-Keyboard-Protocol#keyboard-side-schemaitcs

Title: Re: IBM model F XT component identification
Post by: Fallen_Angel72 on Mon, 07 June 2021, 15:31:39

Wow, thank you! I didn't know this existed