[Coco] video composite on korean coco 26-3134A

Fri Oct 3 17:30:45 EDT 2014

type CLOAD and listen for the relay.

On Fri, Oct 3, 2014 at 3:29 PM, Zippster <zippster278 at gmail.com> wrote:

> Check for a clock signal and address/data line activity at the cpu.
>
> -Ed
>
>
> On Oct 3, 2014, at 2:16 PM, didier derny <didier at aida.org> wrote:
>
> > I'll probably order a pcb
> >
> > My main problem, is that I have absolutely no idea if the coco 2 is
> working
> > at all
> > I tested inside the modulator but I've not seen any signal looking like a
> > video signal
> > (no synchro seen)
> >
> > Is there any other way to know if it is dead or alive ?
> >
> > --
> > didier
> >
> >
> > -----Message d'origine-----
> > De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Zippster
> > Envoyé : vendredi 3 octobre 2014 19:21
> > À : CoCoList for Color Computer Enthusiasts
> > Objet : Re: [Coco] video composite on korean coco 26-3134A
> >
> > Mike,
> >
> > I made this board to replace the RF modulator box that was in my Korean
> > CoCo2.
> > I removed the modulator, and soldered pin headers in where the inputs to
> the
> > modulator are.  Y, øA, øB, CHB, CLK, Sound, and +5v are all in these
> > headers.
> > The area underneath the modulator is pretty much all ground plane,
> allowing
> > me to drill mounting holes for the board, and use standoffs to attach it.
> >
> > Corresponding female headers on the board then just plug into the
> > motherboard (except for
> > 1 ground wire that needs to be attached).  Then I made a cutout in the
> back
> > of the CoCo case, basically expanding where the RF connector was.  It
> makes
> > for a pretty neat installation.
> > (I’ll put some more pics up later).
> >
> > I’m not sure if all Korean CoCo2 main boards have the same layout in the
> > modulator area, but  I think we may have the same model, so it should
> fit.
> >
> > I know other CC2’s have differing layouts for the modulator area, but
> it’s
> > easy enough to lay out a board to fit those (with measurements).
> >
> > I had also thought of the idea of a board plugging into the MC6847
> socket,
> > and moving it to onto the board, which is a good one.  I’m planing on
> this
> > approach for a Component Video board I’m working on.  It would be pretty
> > easy to socket non-socketed 6847’s if you’re willing to sacrifice the
> chip
> > (utsource has them, I think I paid $5ea for five).
> >
> > - Ed
> >
> >
> >
> > On Oct 3, 2014, at 11:17 AM, mike at borncoco.com wrote:
> >
> >> Ed, I ordered some of your boards from OSHpark. Nice layout! I'll have
> to
> > open up a Korean CoCo 2 this weekend to see how you made the connections
> to
> > the motherboard. Any info on what you must remove? If you already
> discussed
> > this here, just say so and I'll look in the archives later. As you said,
> it
> > would not be difficult to use clip leads to make the connections for any
> > CoCo2. I am still interested in creating a version that can be plugged
> into
> > the 6847 socket. I know the other puzzle is that some models of the CoCo
> 2
> > have the RF modulator box mounted in different ways - some at 90 degrees
> to
> > the motherboard.
> >>
> >> Great work on the board and I appreciate the time and effort you put
> into
> > this and sharing it with all of us! I look forward to assembling the
> boards
> > when they arrive.
> >>
> >> Cheers,
> >> -Mike
> >>
> >> -----Original Message-----
> >> From: "Zippster" <zippster278 at gmail.com>
> >> Sent: Friday, October 3, 2014 11:53am
> >> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> >> Subject: Re: [Coco] video composite on korean coco 26-3134A
> >>
> >> There was when it was sent, not sure what’s stripping them out.
> >>
> >> I’ll list them this way…
> >>
> >> https://sites.google.com/site/thezippsterzone/home/coco2-projects
> >>
> >> https://oshpark.com/shared_projects/lHtMJ67Z
> >>
> >> -Ed
> >>
> >>
> >> On Oct 3, 2014, at 10:48 AM, Al Hartman <alhartman6 at optonline.net>
> wrote:
> >>
> >>> There's no link in that message...
> >>>
> >>> -[ Al ]-
> >>>
> >>> -----Original Message----- From: Zippster
> >>> Sent: Friday, October 03, 2014 10:34 AM
> >>> To: CoCoList for Color Computer Enthusiasts
> >>> Subject: Re: [Coco] video composite on korean coco 26-3134A
> >>>
> >>> Hey guys,
> >>>
> >>> You may have missed my earlier post.  I did a version of this circuit
> in
> > Eagle.
> >>> Sound output is included.
> >>>
> >>> The files are in the zip on this page.  CoCo2 Projects (Tandy Color
> >>> Computer 2) - The Zippster Zone
> >>>
> >>> I put it up as a shared project on OSHPark.  OSH Park ~ Coco2
> >>> Composite Out (Type 01) Rev 03
> >>>
> >>> I laid the board out to replace the RF modulator in my Korean
> >>> CoCo2’s, but as long as you get the signals to it, you could mount it
> > anywhere.
> >>>
> >>> -Ed
> >>>
> >>>
> >>> On Oct 3, 2014, at 7:20 AM, Michael Rowen <mike at borncoco.com> wrote:
> >>>
> >>>> John is indeed correct. I have built the simple circuit that includes
> a
> > 1372 that connects to the signal from the 6847. It works well on every
> > monitor I've used with a CoCo 2. The circuit is in the data sheet for the
> > 6847. I have not had the time to create a PCB with Eagle. Some CoCos have
> > the 6847 socketed, so it would be easy to make a board that plugs into
> that
> > 40 pin socket, with the 6847 plugging into the board. CoCo 2s with a
> > soldered 6847, would require 7-8 clip leads, but can be done. I have
> bread
> > boarded this on a CoCo 2. This was the same method used by the Colorware
> > adapter. I scored one of these at last year's CoCo fest. Its circuit uses
> > more caps, but the principle is the same. I have not found any
> significant
> > quality differences using the reference circuit. Clean and sharp. Any
> Eagle
> > experts with some time on their hands to create the PCB files?? :) It
> will
> > probably be Christmas time before I get the chunk of time to tackle this.
> > I'm a newbie with Eaglecad. I'll try to post a video this weekend.
> >>>>
> >>>> Cheers,
> >>>> Mike Rowen
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> "John W. Linville" <linville at tuxdriver.com> wrote:
> >>>>
> >>>>> NTSC CoCo2's use a modulator that does _not_ take a composite video
> >>>>> input.
> >>>>>
> >>>>> The 6847 outputs signals called Y, phiA, and phiB.  These are
> >>>>> (very) roughly analogous to the YIQ signals that form a composite
> video
> > signal.
> >>>>> A Motorola 1372 chip is used to combine those signals into
> >>>>> something useful.  The 1372 chip can produce either a baseband
> >>>>> composite video signal or (by use of an RF tank circuit) a
> > TV-compatible radio signal.
> >>>>>
> >>>>> On the Coco1, the 1372 only produced a composite video signal that
> >>>>> was then fed (along with the audio signal) to an off the shelf RF
> >>>>> modulator.  On the CoCo2, the 1372 chip is only included as part of
> >>>>> the RF modulator itself.  The Y, phiA, and phiB signals go straight
> >>>>> to the modulator where the RF-equipped 1372 turns them into a TV
> > signal.
> >>>>>
> >>>>> I'm not sure if there is a pristine composite video signal
> >>>>> available anywhere inside the RF modulator on a CoCo2.  I was never
> >>>>> able to find one, FWIW.  You probably need to pull the modulator
> >>>>> and build a new 1372-based circuit to replace it.
> >>>>>
> >>>>> Good luck!
> >>>>>
> >>>>> John
> >>>>>
> >>>>> P.S.  It sounds like the PAL CoCo2 might be designed more like the
> >>>>> CoCo1 in this regard.  Of course, that only helps you if you are
> >>>>> using a PAL CoCo2... :-)
> >>>>>
> >>>>> On Thu, Oct 02, 2014 at 09:56:31PM +0200, didier derny wrote:
> >>>>>> Hi,
> >>>>>>
> >>>>>> I tried but no success...
> >>>>>>
> >>>>>> I don’t have any image on tv (connected to the antenna) No idea if
> >>>>>> the coco 2 is broken or if my tv is unable to process the signal
> >>>>>>
> >>>>>> With the oscilloscope I've not been a able to find a composite
> >>>>>> signal Inside the modulator...
> >>>>>>
> >>>>>> Any idea ?
> >>>>>>
> >>>>>> Thanks
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> didier
> >>>>>>
> >>>>>> -----Message d'origine-----
> >>>>>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de
> >>>>>> Simon Jonassen Envoyé : samedi 27 septembre 2014 16:26 À :
> >>>>>> 'CoCoList for Color Computer Enthusiasts'
> >>>>>> Objet : Re: [Coco] video composite on korean coco 26-3134A
> >>>>>>
> >>>>>> Hey....
> >>>>>>
> >>>>>> I did mine by tapping into the feeds that go directly to the rf
> >>>>>> modulator....
> >>>>>>
> >>>>>> A couple of shielded wires soldered on to the pins and 2 rca jacks
> >>>>>> on the rear of the case (audio/video)
> >>>>>>
> >>>>>> Works fine... No extra components needed (PAL machine)...
> >>>>>>
> >>>>>> /Simon :-)
> >>>>>>
> >>>>>>
> >>>>>> -----Oprindelig meddelelse-----
> >>>>>> Fra: Coco [mailto:coco-bounces at maltedmedia.com] På vegne af didier
> >>>>>> derny
> >>>>>> Sendt: 27. september 2014 13:23
> >>>>>> Til: 'CoCoList for Color Computer Enthusiasts'
> >>>>>> Emne: [Coco] video composite on korean coco 26-3134A
> >>>>>>
> >>>>>> Hi
> >>>>>>
> >>>>>> Is there an easy way to get a video composite signal on this
> machine ?
> >>>>>>
> >>>>>> I guess a video composite signal or something approaching should
> >>>>>> be found Somewhere near the modulator or inside the modulator ?
> >>>>>>
> >>>>>>
> >>>>>> Thanks
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> Coco mailing list
> >>>>>> Coco at maltedmedia.com
> >>>>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>>>> -----
> >>>>>> Ingen virus fundet i denne meddelelse.
> >>>>>> Kontrolleret af AVG - www.avg.com
> >>>>>> Version: 2012.0.2247 / Virusdatabase: 4031/7782 - Udgivelsesdato:
> >>>>>> 27-09-2014
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> Coco mailing list
> >>>>>> Coco at maltedmedia.com
> >>>>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> Coco mailing list
> >>>>>> Coco at maltedmedia.com
> >>>>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>>>>
> >>>>>
> >>>>> --
> >>>>> John W. Linville Someday the world will need a hero, and you
> >>>>> linville at tuxdriver.com might be all we have.  Be ready.
> >>>>>
> >>>>> --
> >>>>> Coco mailing list
> >>>>> Coco at maltedmedia.com
> >>>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>>
> >>>> --
> >>>> Coco mailing list
> >>>> Coco at maltedmedia.com
> >>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>
> >>>
> >>> --
> >>> Coco mailing list
> >>> Coco at maltedmedia.com
> >>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>
> >>> --
> >>> Coco mailing list
> >>> Coco at maltedmedia.com
> >>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>
> >>
> >> --
> >> Coco mailing list
> >> Coco at maltedmedia.com
> >> https://pairlist5.pair.net/mailman/listinfo/coco
> >>
> >>
> >>
> >> --
> >> Coco mailing list
> >> Coco at maltedmedia.com
> >> https://pairlist5.pair.net/mailman/listinfo/coco
> >
> >
> > --
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> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco
> >
> >
> > --
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>
>
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