[Coco] Composite Video Mod for CoCo1

[Fedor Steeman]

Hi,

As translation slowly progresses (
http://www.cocopedia.com/wiki/index.php?title=Koen_Vaartjes_Video_Mod), I
realized that these are actually only mounting instructions, not so much
assembly instructions. It is just a manual that accompanied the readily
assembled card kit. However, it does some schematics, but not very
detailed, i.e. you can see the components, but not the connections.

Still useful? Or should I try to remove the card and makes some pictures so
the connections are made clear? I am not that very well-versed with
electronics...

Cheers,
Fedor

On 11 December 2012 14:28, Fedor Steeman <petrander at gmail.com> wrote:

>
>> > On 11 December 2012 12:29, Daniel Campos <daniel.campus at gmail.com>
>> wrote:
>> >>
>> >> Hi Fedor,
>> >>
>> >> If you could do a job translating that document would be great! As far
>> >> as my research goes about those mods on the web, that of yours is the
>> >> only one available so far.
>> >>
>> >> Thanks,
>> >> Daniel
>> >>
>> >> 2012/12/11 Fedor Steeman <petrander at gmail.com>:
>> >> > Hi Daniel,
>> >> >
>> >> > That looks awesome, and reminds of the time where the modded CoCo
>> still
>> >> > was
>> >> > outputting video!
>> >> >
>> >> > I still haven't gotten around of translating and redoing the
>> schematics
>> >> > in
>> >> > digital format, but it is still on my to-do list for those
>> interested.
>> >> >
>> >> > Cheers,
>> >> > Fedor
>> >> >
>> >> > On 6 December 2012 14:05, Daniel Campos <daniel.campus at gmail.com>
>> wrote:
>> >> >>
>> >> >> Hi Fedor,
>> >> >>
>> >> >> Yes, I saw your post some time ago but the hand written schematics
>> are
>> >> >> not so clear to understand. For the pictures, I can guess that some
>> >> >> wireup got loose on transport.
>> >> >>
>> >> >> I just have done the mod described on the MC6847 datasheet, and
>> after
>> >> >> a fine tunning using trimpots, a believe I came with a good overall
>> >> >> image. The pictures bellow, shown the final result on my Color64:
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818574442902576802
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818574744878407410
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818575311739711346
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818575226684298914
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818574448002174674
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818574792157143906
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818574797580859266
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> https://picasaweb.google.com/109345699838454178536/LZColor64#5818575156296252562
>> >> >>
>> >> >>
>> >> >> Tweaking the trimpots yesterday I came with a good improve on
>> contrast
>> >> >> since those pictures were taken.
>> >> >>
>> >> >> Thanks,
>> >> >> Daniel
>> >> >>
>> >> >>
>> >> >> 2012/12/6 Fedor Steeman <petrander at gmail.com>:
>> >> >> > Hi Daniel,
>> >> >> >
>> >> >> > If you search the list, you can read that I posted about this
>> subject
>> >> >> > a
>> >> >> > few
>> >> >> > times already earlier.
>> >> >> >
>> >> >> > In short, I acquired a CoCo2 with such a composite video mod that
>> >> >> > worked
>> >> >> > fine, until I transported it somewhere at a certain moment. I
>> think
>> >> >> > something came loose or short-circuited, because now I only get a
>> >> >> > black
>> >> >> > screen. It can probably easily be fixed, but I am not that skilled
>> >> >> > enough to
>> >> >> > do it.
>> >> >> >
>> >> >> > The video mod is based on the following manual (in Dutch):
>> >> >> > http://www.steeman.dk/CoCoManuals/VideoMod_(KoenVaartjes).pdf
>> >> >> >
>> >> >> > Here are some pictures of it:
>> >> >> >
>> >> >> >
>> >> >> >
>> https://picasaweb.google.com/115146243402896969496/CoCoVideoMod?authuser=0&authkey=Gv1sRgCKCWiaq64ompugE&feat=directlink
>> >> >> >
>> >> >> > Cheers,
>> >> >> > Fedor
>> >> >> >
>> >> >> > On 3 December 2012 13:48, Daniel Campos <daniel.campus at gmail.com>
>> >> >> > wrote:
>> >> >> >>
>> >> >> >> Hello,
>> >> >> >>
>> >> >> >> Since I got the Color64 (Coco1 clone) his image, even already
>> having
>> >> >> >> a
>> >> >> >> composite video output, have always disturbed me with a crap
>> image
>> >> >> >> compared to other CoCo machines. So I began to try to correct
>> that
>> >> >> >> and
>> >> >> >> removed the entire transcoder analog pcb that came with the
>> computer
>> >> >> >> and used the schematic bellow to try to have a better composite
>> >> >> >> output:
>> >> >> >>
>> >> >> >> http://www.victortrucco.com/Diversos/MC1000/SaidaAV.JPG
>> >> >> >>
>> >> >> >> The schematic above is largelly based on the driver for color
>> >> >> >> composite video that is showed on the 6847 datasheet. After build
>> >> >> >> the
>> >> >> >> mod, image is great on text mode, sharp and crispy, the problem
>> >> >> >> begans
>> >> >> >> when I got to the graphics mode using artifacting. For example,
>> on
>> >> >> >> Outhouse, the initial screen should be red, but appears with a
>> very
>> >> >> >> pink saturated color, it's impossible to read. Other games, like
>> >> >> >> Draconian and Galagon got very saturated too.
>> >> >> >>
>> >> >> >> My question is, someone here have done any of the scematics
>> bellow
>> >> >> >> and
>> >> >> >> worked fine on a LCD monitor with composite video ?
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> http://www.retrocomputers.eu/wiki/index.php/Tandy_TRS-80_Color_Computer_(CoCo)_Composite_Video_Mod
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> http://sd2cx1.webring.org/l/rd?ring=coco;id=1;url=http%3A%2F%2Fwebspace%2Ewebring%2Ecom%2Fpeople%2Fvt%2Ftheother_bob%2Fcoco_page%2Fccprojects%2Ehtm
>> >> >> >>
>> >> >> >> Any suggestion would be higly appreciated. :)
>> >> >> >>
>> >> >> >> Thanks,
>> >> >> >> Daniel
>> >> >> >>
>> >> >> >> --
>> >> >> >> Coco mailing list
>> >> >> >> Coco at maltedmedia.com
>> >> >> >> http://five.pairlist.net/mailman/listinfo/coco
>> >> >> >
>> >> >> >
>> >> >
>> >> >
>> >
>> >
>>
>
>