[Coco] Another rare brazilian coco clone...

[Daniel Campos]

Hi Dennis,

The circuit I used is based on the schematic present at page 12 of the 
MC6847 datasheet:

http://people.ece.cornell.edu/land/courses/ece4760/ideas/mc6847.pdf

In the place of the 3.9K and 3.3K resistors, I changed both for 10K 
resistors. The 470 Ohms resistor I removed. In the place of the 560 Ohm 
resistor I put a 1K trimpot for fine tunning.
On mine I also put two trimpots in pulldown on both B-Y and R-Y lines 
that come from 6847 to 1372. It helps both to regulate colors and 
decrease color saturation.
All else remains exactly the same as on the datasheet.

I used this formula on both MX-1600 and on the Color64, another Coco 
clone I have:

https://picasaweb.google.com/109345699838454178536/LZColor64#

Regards,
Daniel

Em 27/01/2013 23:25, Denis Bisson escreveu:
> Daniel Campos <daniel.campus at ...> writes:
> ...
>> Last week I acquired another rare brazilian coco clone, the Dynacom MX-1600.
>> https://picasaweb.google.com/109345699838454178536/DynacomMX1600
>> It came on bad shape and not working, but after some work, it's fully
>> functional again.
> ...
>
>    Hi!
>
>    Nice picture and work!
>
> May I asked you if you could share with me the MC1472 circuit you made?
>
> I've already made something like that two times in the past to convert regular
> COCO to provide NTSC signal directly. But according to your picture, you have
> much more potentiometers than the application note I am using for that patch.
> I would be curious to use your circuit as your picture seems to show a better
> result.
>
> Thanks.
>
> Dennis.
>
>
>
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