[Coco] Weird CoCo 2 keyboard problem -- any ideas?

Arthur Flexser flexser at fiu.edu
Mon Apr 1 16:23:40 EDT 2013


Yes, but the shift key worked in combination with keys not in that column.
Why should it work at all if that column has a continuity problem?

Art

On Mon, Apr 1, 2013 at 3:31 PM, Christopher R. Hawks <chawks at dls.net> wrote:

> On Mon, 1 Apr 2013 14:02:52 -0400
> Arthur Flexser <flexser at fiu.edu> wrote:
>
> > My recollection from having once opened up a CoCo 1 keyboard is that
> > there are no diodes, just contacts that get made when a key is
> > pressed.
> >
> > If pressing the shift key was opening a broken trace, I'd expect it to
> > matter which of the two shift keys you used, and you said it made no
> > difference.
> >
> > So, I wouldn't entirely take the ribbon cable out of the running just
> > yet, though I'm still puzzled as to why the problem with the shift
> > key should affect just one keyboard column.
>
>         'Cause that is the column that the shift key is in.
>
> > Maybe try simulating a keypress by momentarily shorting a row and a
> > column line in the ribbon cable and see if you get the expected
> > output in all cases, and in particular whether you can type a
> > question mark while simulating the shift key being down.
> > (Admittedly, it seems like this requires 3 hands.)
> >
> > Art
>
> Christopher R. Hawks
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