[Coco] Help COCO-1 Keyboard

Joel Ewy jcewy at swbell.net
Sun Apr 8 20:43:42 EDT 2007

John T Chasteen wrote:
> ...
> I also have a replacement keyboard but the connector is a flat ribbon on
> the keyboard and the connector on the motherboard is a male connector.
> Any
> suggestions how I can solve this connection problem?
Ok, the gallery is down at CoCo3.com right now.  I'm sure Roger doesn't
need any more pressure to get it back up.  But the timing is
unfortunate, because I have a photo there showing how I solved this
problem.  What I did was admittedly a little kludgy, but works well and
doesn't do anything irreversible to the CoCo.  I had an extra CoCo 3
keyboard left over after a repack project that made use of a Bob Puppo
XT keyboard interface.  So I put it in my original CoCo 1.  The poor old
chicklet keyboard in it had seen better days -- though it never was all
that nice to type on in the first place.  :)

I found a single-row IDC header socket in one of my junk boxes.  (Or
maybe this was one of the original connectors for the cable that runs
between the CoCo 1 keyboard and the Color Computer.  It's been a while. 
If so, then the hack does do a little damage to the CoCo, but still
eliminates the need to unsolder connectors from the motherboard.)  I
attached this to a short length of ribbon cable with a 34-pin card edge
connector on one end, hacked off of an old floppy cable.  Only
every-other conductor of the ribbon cable was needed -- the remainder
were left unconnected.  Make sure you select the right ones.  Check it
out with your Ohm meter if there's any uncertainty -- or even if there

I plugged the header socket into the keyboard header pins on the CoCo's
circuit board.  Then I inserted the flexible mylar PC from the CoCo 3's
keyboard into the card edge connector.  Note that the edge connector
selected is not one that has a directional key, otherwise the keyboard
connector wouldn't slide in, since it lacks a corresponding notch.  The
mylar flexible PC isn't thick enough to stay in the card edge connector,
let alone make good contact.  So I took a band saw to an old PC board,
and cut a section without any traces, just wide and deep enough to slide
in the edge connector and force the CoCo 3's thin keyboard connector
firmly against the spring contacts of the edge connector. (An
appropriately cut piece of cardboard might also work.)  During this
process, the flexible PC must be aligned to one side of the edge
connector, because it is actually about 1 pin narrower than the 34-pin
floppy connector.  But once the PCB cutout insert is in place, the CoCo
3 keyboard connector is pretty tightly secured in the right place.

I don't know whether this exact hack will work for you or not, but it
might give you some ideas.  When Roger gets the CoCo 3 forums back up,
look through my gallery and find the picture I took.  It might make this
lengthy explanation a little more clear.

Joel Ewy (JOELAV)
> ...
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