[Coco] Finally RGB from a coco 2

[Zippster]

I don’t know.  

I asked Fred about schematics on Atari Age, he declined, saying he wanted to offer kits and upgrades.

My guess would be the transistor circuit inverts Y and level (amplitude) adjusts Y, øA, and øB.
The small board probably handles component to RGB matrix conversion, the the HDMI converter
box as scan-doubler to 31.4khz for the monitor.

- Ed


> On Jul 1, 2015, at 1:30 PM, didier derny <didier at aida.org> wrote:
> 
> Thanks Ed :)
> 
> is it the technique used in he Alice 4k ?  the alice 4k Uses a lot of transistors to convert
> the signal from the 6847 into RGB  (it is more complex it also convert 525 lines to 625 lines)
> 
> I'm using the same scart to hdmi  not perfect but works well
> 
> 
> --
> didier
> 
> 
> On 01/07/2015 20:22, Zippster wrote:
>> Fred, I put the pics on my google drive so these guys can see them, I hope that’s alright.
>> 
>> The pics show a breadboard with a circuit using 6 transistors and several resistors, along with
>> the green alpha startup screen on a monitor and small tv.  Looks like the HDMI converter with
>> the RGB on the monitor, RF on the little TV.
>> 
>> - Ed
>> 
>> 
>> 
>> The text from his Atari Age post…
>> 
>> "I have been working on this coco 2 rgb mod for sometime.. I unfortunately got laid off last week, but  on the flip side, with the extra time, I have finally got this working perfect.  It basically turns the r-y b-y into RGB. Then I run it into a scart to hdmi converter. The picture is of 1080i output. Check it out."
>> 
>> And pics...
>> 
>> <https://drive.google.com/open?id=0B1sgl615FlGnQWVuUHdGamRLS1E <https://drive.google.com/open?id=0B1sgl615FlGnQWVuUHdGamRLS1E>>
>> <https://drive.google.com/open?id=0B1sgl615FlGnNmtxRjhhMFlNSEE <https://drive.google.com/open?id=0B1sgl615FlGnNmtxRjhhMFlNSEE>>
>> <https://drive.google.com/open?id=0B1sgl615FlGnNmtxRjhhMFlNSEE <https://drive.google.com/open?id=0B1sgl615FlGnNmtxRjhhMFlNSEE>>
>> 
>> 
>> 
>>> On Jul 1, 2015, at 1:09 PM, Joe Grubbs <jsgrubbs at hotmail.com> wrote:
>>> 
>>> How accurate are the colors? The traditional problem has been proper level translation so that red appears truly red, orange appears truly orange, and black is truly black (and not blue-ish), etc.
>>> 
>>> 
>>> 
>>> 
>>>> To: coco at maltedmedia.com
>>>> From: Fredkono at gmail.com
>>>> Date: Wed, 1 Jul 2015 16:55:43 +0000
>>>> Subject: [Coco] Finally RGB from a coco 2
>>>> 
>>>> I finally got a perfect working circuit to run RGB from a COCO 2. Check it
>>>> out on Atariage.
>>>> 
>>>> I am new to this forum so I cam not sure how to post pictures.
>>>> 
>>>> http://atariage.com/forums/topic/239999-rgb-out-of-a-coco-2-i-finally-
>>>> have-a-working-prototype-looks-great/
>>>> 
>>>> 
>>