[Coco] S-Video mod for Coco1

[Ken H.]

I tested LM1889 pin 13 on my Dragon with a multimeter and it's 10V :(

THANKS Luis!  Your persistent warnings probably saved my monitor/composite
adapter.

It's strange though because the Spectrum guys are clearly sending LM1889 pin
13 directly to the s-vga chroma input.
http://www.retrowiki.es/fororw/viewtopic.php?f=667&t=29522

Is anyone familiar with the s-vga specs? Maybe it can take 10V??






On Tue, Oct 1, 2013 at 4:45 PM, Luis Antoniosi (CoCoDemus) <
retrocanada76 at gmail.com> wrote:

> according to the scheme you post the output is NOT 12V otherwise it would
> burn your monitor.
>
> just measure it with a multimeter before.
>
> This should work on a dragon.
>
>
> On Tue, Oct 1, 2013 at 8:44 AM, Ken H. <dragon.atv at gmail.com> wrote:
>
> > The input for the LM1889 is 12V.
> >
> > But I think that the chroma subcarrier output on pin 13 is not, if we can
> > trust the Spectrum service manual
> >
> >
> http://www.1000bit.it/support/manuali/sinclair/zxspectrum/sm/sec4_4.html#ic14
> >
> >
> >
> > On Tue, Oct 1, 2013 at 2:45 PM, Retro Canada <retrocanada76 at gmail.com
> > >wrote:
> >
> > > but is 12v right ?
> > >
> > > On 2013-10-01, at 3:40 AM, "Ken H." <dragon.atv at gmail.com> wrote:
> > >
> > > Luis, your bet on pin 13 of the LM1889 is right on target!
> > >
> > > The ZX Spectrum also has the LM1889 (IC14) and pin 13 is indeed used
> for
> > > its s-video mod:
> > > http://www.retrowiki.es/fororw/viewtopic.php?f=667&t=29522
> > >
> > >
> > >
> > > On Mon, Sep 30, 2013 at 10:18 PM, Luis Antoniosi (CoCoDemus) <
> > > retrocanada76 at gmail.com> wrote:
> > >
> > > > Your answer is on IC39. LM1889: It has several chroma inputs. Need to
> > > know
> > > > if one of them is useful. I bet on pin 13 Chroma Subcarrier.
> > > >
> > > >
> > > >
> > > >
> > > > On Mon, Sep 30, 2013 at 3:09 PM, Ken H. <dragon.atv at gmail.com>
> wrote:
> > > >
> > > >> Looking at the Tano motherboard I can't see an MC1372
> > > >> http://archive.worldofdragon.org/images/4/40/Tano64.png
> > > >>
> > > >>
> > > >>
> > > >> On Mon, Sep 30, 2013 at 9:58 PM, Luis Antoniosi (CoCoDemus) <
> > > >> retrocanada76 at gmail.com> wrote:
> > > >>
> > > >>> Is there a chrominance output on it ?
>
>