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

[Stephen H. Fischer]

Pressing the shift key may flex the entire keyboard. Pressing a different 
set of keys along with the shift key may produce different failures or 
success.

There are two shift keys, does it matter which one is used? It was said not, 
try 200 times with each.

The "?" and "/" are right next to the right "shift" key.

I looked at a keyboard removed from a CoCo 1 and it has a very solid PC 
board for the keyboard. (Shift key missing) It was in the CoCo 1 box but has 
no F1 F2 keys?

I once removed the entire plastic matrix from a keyboard and rewired it by 
hand to match a keyboard IC that outputted serial data.

It was a great method to get a keyboard for FLEX. I learned how to write a 
keyboard input routine that handled bounces.

I have a stereo receiver that lost one channel output to the speaker unless 
I pressed the PC board in the right place. It worked for a while then.

SHF



----- Original Message ----- 
From: "Arthur Flexser" <flexser at fiu.edu>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Monday, April 01, 2013 1:23 PM
Subject: Re: [Coco] Weird CoCo 2 keyboard problem -- any ideas?


> 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
>> --
>> There ain't nothin' in this world that's worth being a snot over.
>>             --Larry Wall in <1992Aug19.041614.6963 at netlabs.com>
>>
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