[Coco] Fixing coco2 keyboard traces.

[Arthur Flexser]

I wouldn't think you'd need to entirely repaint all 15 traces with it,
just bridge over a few cracks here and there that probably would show
up if you held the ribbon up to a light.  I've heard of successful
repairs using this method.  One pen should be more than you need.

Thanks for revealing the mystery of the pole barn.

Art

On Sun, Jul 22, 2012 at 4:02 PM, chris <cralt at comcast.net> wrote:
> Brendan,
>
> RadioShack carries that same pen in their stores (they seem to have more and
> more electronic stuff now) but its $20 and reading the package I have the
> same concerns about it working on something flexible. And the amount it
> holds seems very small so I don't know if one pen will do all 15 traces. It
> would be a $40 risk for a 16K CB coco :-/
>
> If I can't come up with another way to shore up the traces I may try
> bringing the plug to the good traces. I could remove it off the board and
> extend it with normal jumper wires up to the keyboard.
>
>
>
>
> On Jul 22, 2012, at 8:00 AM, Brendan Donahe wrote:
>
>> I've fixed non-flexible PCBs using a conductive pen, such as this one:
>>
>> http://www.mcmelectronics.com/product/CAIG-LABORATORIES-CW100P-/200-175
>>
>> I'm not sure if this would work for the flexible "ribbon" or not, though.
>>
>> Brendan
>> On Jul 21, 2012 10:12 PM, <cralt at comcast.net> wrote:
>>
>>> I saved a lowly 16K Coco2 non-ECB from a poll barn. It was in ruff shape
>>> but I cleaned it up and got it working. The keyboard was totally full of
>>> trash so i spend the morning dissembling it and washing each part off. It
>>> all went back together good but only has a few keys working. I swapped
>>> keyboards with another coco and verified it is the keyboard that is the
>>> issue. The issue seems to be the ribbon that exits the keyboard. If I
>>> bypass this with jumper clips I can get the keys to work. It seems the
>>> resistance is higher on the traces on the exposed ribbon section then it
>>> is
>>> on the traces that are in the keyboard. I can also see light through the
>>> traces on the ribbon section.
>>>
>>> I tried coloring over the tops of the traces with a #2 pencil but it
>>> didnt
>>> help. It seems the coco wants to see zero ohms before it registers a
>>> keystroke. Its only seeing 4-5 ohms through the bad traces.
>>>
>>> Is there any way to rebuild the traces or some how attach jumper wires to
>>> the membrane? I dont think I will be able to solder to them with out
>>> melting the plastic. Any one have any tricks to fix this?
>>>
>>> Thanks
>>> -chris
>>>
>>>
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>>
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