[Coco] Trying to get a KoKo2 working

Sat Aug 24 23:58:05 EDT 2013

check for capacitors C15 and C18 if they are short and cause the keyboard
malfuncion.

Also check for a ground short to any of the keyboard row inputs pins 2 to 9
in IC7.

On Sat, Aug 24, 2013 at 9:21 PM, Chris Osborn <fozztexx at fozztexx.com> wrote:

> I got a KoKo 2 off eBay a few days ago, and it boots up, but the keyboard
> doesn't work at all. I've been trying to hunt down schematics but so far
> have only found schematics for the CoCo 1 & 3, nothing for the 2.
>
> I pulled out the logic probe to test the 6821, and I do see signals, but
> not like I'd expect. Pin 3 is stays high, and pin 12 is oscillating. I
> would expect since it should be scanning the matrix that several of the
> pins to be oscillating as it scans the matrix. Is the PIA dead, or could it
> be something else?
>
>
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-- 
Long live the CoCo