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geekhack Community => Keyboards => Topic started by: rowdy on Mon, 08 July 2013, 21:03:51
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I have recently acquired two Model M keyboards.
One has (had) a non-removable cable which someone has thoughtfully snipped about 5cm out from the case.
I found this link:
http://www.vogons.org/viewtopic.php?t=32544&sid=c34571ca613148056265507e7edc871b
which details the steps someone took to replace such a cable.
Does that process seem reasonable?
Looks like he used a standard PS/2 cable, of which I have a few. Is that a good idea, or is there a more IBMish cable that would suit better?
He also recommended putting ferrite beads on the cable - is that also recommended? If so, where? Just one at the keyboard end (inside the case, as he did)?
Thanks.
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The ferrite beads act as inductors and help to cancel out any unwanted ripples or spikes. Were you in the US I'd mail you a couple, but you can sometimes find them pretty cheap. Any PS/2 cable should work, but you might want to try a beige one to look nicer.
What I would do is drop a teensy in there, and put soarer's code on it, then run a USB cable out. Up to you of course.
Ferrite beads (I believe) can go anywhere on the cable, but it's usually more useful to have them near on end.
One issue I have run into with a cable swap (that you may or may not) is ending up with a hole in the keyboard where the cable comes out. You may want to look into a cable gland to provide some strain relief and help fill up the hole a little.
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I can get the beads locally, something like this is sufficiently cheap: http://www.jaycar.com.au/productView.asp?ID=LO1238
As for the USB mods, that would be ideal (still waiting for that PS/2 to USB adaptor ...) but I don't even know if the keyboards work at this stage.
I have lots of old robber dome keyboards of various colours, so I can salvage a cable from there just to see if it works.
As for the hole, a small grommet of some description should suffice. Something like this: http://www.jaycar.com.au/productView.asp?ID=HP0718
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The cable on my Unicomp (PS2, "non removeable") looks like this :
http://www.clickykeyboards.com/index.cfm/fa/items.main/parentcat/33739/subcatid/0/id/574261 (http://www.clickykeyboards.com/index.cfm/fa/items.main/parentcat/33739/subcatid/0/id/574261)
(http://www.clickykeyboard.com/2013/jul05/001.jpg)
Would imagine the Attached Cable part that Unicomp sells on their site is the same.
http://pckeyboard.com/page/Cables/ACable (http://pckeyboard.com/page/Cables/ACable)
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Yes, a shame they do not show a picture of it. Still, I don't even know if the boards work, so I might start with the non-removable cable one, solder a replacement PS/2 cable on to it (as per the article I linked), and see if it works. But once I get that far I would probably leave it like that if it worked.