[Coco] Is MM/1 to SCART practical?

[David Ladd]

Well in this case I don't have to much data from the documentation I have
about the video signal stuff.

I know I can use a CM-8 monitor on my MM/1 without any problems.  I also
use to have a Magnavox monitor I used on the MM/1 and CoCo3.  Sadly the
Magnavox died first and then my CM-8 died not long after.

So that is one of the reasons I got the RGB2VGA hoping I could use it on
both.  The SYNC seems to work on the RGB2VGA, but the colors are so dark on
the VGA monitor with the MM/1 I can't read the output.

The other thing is I don't have the tools to test all this stuff.

That is why I was hoping someone out there with a MM/1 might know or have
more experiance with this.

On Saturday, August 22, 2015, Barry Nelson <barry.nelson at amobiledevice.com>
wrote:

> I had problems producing a composite sync with the proper wave form shape
> inexpensively which is why I steal it from the composite video port.
> Besides, the SCART video standard actually expects a full composite video
> signal on that pin, although it  will work in RGB mode if you just supply a
> valid composite sync. Also, the MM/1 probably has a different video out
> circuit. I have no idea if it's signal parameters fall close enough to
> SCART 480i video to make this work. The CoCo 3's RGB output just happens to
> have the same peak to peak voltages, timings, and everything that happen to
> coincidently match what SCART expects for a 480i RGB signal which is why
> this works. Really the CoCo 3 effectively outputs an SCART standard signal,
> it is just not wired to an SCART plug. That is why this works. I do not
> know if that is the case for the MM/1, you will need to research that.
> SCART can accept either a 50Hz (PAL) or 60Hz (NTSC) vertical sync rate at
> either 15khz horizontal or 30khz horizontal sync. It expects the signals on
> the RGB lines and the composite sync to be .7 volts peak to peak, and the
> sync must be a negative going sync pulse.
>
> On Aug 21, 2015, at 7:19 PM, coco-request at maltedmedia.com <javascript:;>
> wrote:
>
> > Date: Fri, 21 Aug 2015 16:02:12 -0500
> > From: David Ladd <davidwladd at gmail.com <javascript:;>>
> > To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com
> <javascript:;>>
> > Subject: Re: [Coco] CoCo 3 RGB to SCART to HDMI update
> > Message-ID:
> >       <
> CAHW2jkC3YsmPOYgOtpPYzH48s22BnkzTuGaakVvDH79Lh113qg at mail.gmail.com
> <javascript:;>>
> > Content-Type: text/plain; charset=UTF-8
> >
> > I wonder if this would be a good option to try on my MM/1.
> >
> > I have tried the RGB2VGA project on my MM/1 and sadly it doesn't work as
> I
> > had hoped.
> >
> > Thanks for the write up on this.  Will give me a direction to try with my
> > MM/1.  Though sadly I wont have the composite video source though.  I
> > wonder what is the best solution for producing a composite sync out of
> the
> > H and V sync lines.
> >
> > +----------+
> > |David Ladd|
> > +----------+
>
>
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