[Coco] CoCo2 Composite Boards (update)

[Gene Heskett]

On Friday 27 February 2015 10:50:51 Zippster wrote:
> Hi Gene,
>
> These are small PCBs that replace the RF modulator can on CoCo2’s to
> provide a composite output (with sound).  Uses a 2 conductor mini-jack
> (with ground of course), and doesn’t require any case modification on the
> CoCo.
>
> Does require removing the RF box on the motherboard (pretty easy with a
> temp controlled iron). Based on the CoCo2 educational model’s factory
> composite board, which I RE’d.
>
> Schematic here —>  <REDRAWN Schematicsch.jpg
> <https://7013705b-a-62cb3a1a-s-sites.googlegroups.com/site/thezippsterzone/
>coco2-composite-board-2/schematic-and-circuit-commentary/REDRAWN%20Schematic
>sch.jpg?attachauth=ANoY7cqtYsQJf0Y6moe0E4BRyl9T-t9_N3YMiYTLr1aWdX63Wu8rANRqW
>vXwrSHV6RrgmyEVWzA6Dt_k4SM5MDF_bfsOxVqz2_jPZFaAiUS_XRArPvod7RjyY57MdcuIvRS5l
>TuEciAUqCiEoVeklAthAg5zH5p8ZgXifUb2x6rP5rf8AENII2GRnlSbKSetCQAMbTfGvD1uk-LQK
>tSnGOsri68GNexjw_fRDHj9O7vq0junWm6CyVKkWQ2OQRP_gtzhrrSNq5hYtAWLbDapxBt1Vf7xv
>R44DK83So8mQRIGUS0WGPC7xlCuhdDe_KDfTvo0rykMGdSd&attredirects=0>>
>
> It taps DC and AC current from the mb, running the AC through a voltage
> doubler to operate a 12v regulator.  A 5v regulator runs the 1372.
>
> The channel selection switch grounds the clock signal instead of sending it
> to the 1372 for B&W output, very clear for text only.
>
> Pics of the two board types installed here, as well as a quick pic of the
> B-board output on a ~60” LCD television.
>
> <https://drive.google.com/folderview?id=0B1sgl615FlGnVVFhLTRtbVR4R2M&usp=sh
>aring
> <https://drive.google.com/folderview?id=0B1sgl615FlGnVVFhLTRtbVR4R2M&usp=sh
>aring>>
>
>
> - Ed

My mistake Ed, I thought the thread was the 6 chip motherboard.  This, by the 
way, looks to be quite professionally done.  As I have a small collection of 
1's & 2's, those certainly look "interesting".
>
>
> .
>
> > On Feb 27, 2015, at 9:21 AM, Gene Heskett <gheskett at wdtv.com> wrote:
> >
> > On Friday 27 February 2015 07:26:19 Steven Hirsch wrote:
> >> On Thu, 26 Feb 2015, Zippster wrote:
> >>> I’ll be placing orders for runs of these boards in the next few days,
> >>> so I should have PCBs in a couple of weeks.  I’ll put some pics up
> >>> somewhere (probably tomorrow).
> >>
> >> I'm still interested, Ed.  Keep us posted!
> >>
> >> --
> >
> > And I am curious, and have to ask.  Does this design decode for /CS the
> > same as a real coco, with each valid for a $20 byte wide swath of I/O, or
> > is it taken another step finer so as to make an individual /CS only
> > true-low for a 4 byte wide space?  That would be an absolutely huge
> > improvement.
> >
> > And, can it use, by having the socket for the ribbon of a coco's
> > keyboard, the std coco keyboard?
> >
> > Pix will probably help as the old Chinese proverb goes. ;-)
> > This I assume is only level 1 capable?  eg no gime made out of
> > unobtainium?
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> > soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > Genes Web page <http://geneslinuxbox.net:6309/gene>
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>