[Coco] I think now I have a final design

Luis Antoniosi (CoCoDemus) retrocanada76 at gmail.com
Tue Nov 4 13:20:44 EST 2014


One thing, the vgaout dsub must have the shell grounded. Since the eagle
file doesn't have the 2 pads grounded you probably have to solder a small
jumper on it, between pin 6 and the pad. And make sure the pads are
connected to the outer shell. My dsub connector I had to solder a piece of
solder wick to have it proper grounded. It had some different
non-conductive alloy between then.

Some monitors use the shell as ground.

Luis Felipe Antoniosi



On Tue, Nov 4, 2014 at 12:46 PM, Steven Hirsch <snhirsch at gmail.com> wrote:

> On Tue, 4 Nov 2014, Luis Antoniosi (CoCoDemus) wrote:
>
>  The Apple II connects on the monochrome RCA input (look below the RGBIN
>> connector, there a cinch connector there. You must close the JP1, JP2 and
>> JP3 to have it working. JP1 drives the monochrome signal into the csync
>> signal, jp2 and jp3 drives the hsync and vsync from the LM1881. You need a
>> LM1881 for composite sync.
>>
>
> Ok, thanks.  The schematic symbol for the RCA jack is a bit unfamiliar.
> I'm used to seeing a dashed circle with a dot in the middle.
>
>  I'm using 5% resistors for everything except for the 3x 75 Ohms. These
>> ones
>> you better keep them as 1%. This is the most sensitive part of the
>> circuit.
>> The two caps are 104 i'm using two small orange ceramic discs I don't make
>> any idea about it's tolerance. It's doesn't make difference there.
>>
>
> Thanks for clarifying.  I had a feeling some of them needed to be
> precision resistors.
>
>  For apple ii, I managed to put blue and orange artifact colors (the same
>> on
>> coco2). You can play karateka in colors now. I'm still working on green
>> and
>> pink to see if I can get them as well.
>>
>> You don't need to send me a board. It costs 35 for three I already ordered
>> them. I thought it would cost me more.
>>
>
> I would really like to contribute something to offset your time and
> expense.
>
> Steve
>
>
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>
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