[Coco] RGB cable for Samsung SyncMaster 711mp

[Ken H.]

It's working!!
I now have a perfect RGB image with the Coco3 and Samsung 711mp!
Thanks Luis and Steve for your suggestions.
My problem was with resistor values or improper grounding.

For anyone else who'd like to do it externally (w/o the internal Coco mod),
here are my connections:
CoCo RGB  ---------->   SCART
1,2 + 12v(-)   --->  4,17,21       Ground
3                           ----> 15        Red
4                           ----> 11        Green
5                           ----> 7          Blue
7                           -----> 2,6      Audio
8 ---> 74ls02 pin 8                    HSync
9 ---> 74ls02 pin 9                    VSync
74ls02 pin 10      ------> 20        CSync
12V(+) ---> LM7805 pin 1 ,  SCART pin 8
12V(-)  ---> LM7805 pin 2, 74ls02 pin 7   Ground
LM7805 pin 3 ----> 74ls02 pin 14        VCC 5v
510ohm resistor between SCART pins 8 and 16

Ken



On Fri, Apr 11, 2014 at 2:49 PM, Steven Hirsch <snhirsch at gmail.com> wrote:

> On Thu, 10 Apr 2014, Luis Antoniosi (CoCoDemus) wrote:
>
>  I have to look my cable but I think I followed this:L
>>
>> http://img362.imageshack.us/img362/428/rgbanemoser7.jpg
>>
>> Are you sending the CSync on pin 20 ?
>>
>> The resistor is needed as well.
>>
>
> There are two voltage-controlled pins in the SCART standard:
>
> Pin 8 --> 0-2V = TV Mode
>           5-8V = Wide screen
>           9.5V-12V = AV Mode (aka external input)
>
> (You want AV mode)
>
> Pin 16 --> 0-0.4V = Composite video
>            1-3V = RGB video
>
> (You want RGB)
>
> Not all displays fully implement this, but several of my units here do
> require that both lines be conditioned appropriately.
>
> Steve
>
>
> --
>
>
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