[Coco] MC6847 + Component video

[Daniel Campos]

That circuit works ONLY on TV/Monitors that accept YCbCr signals. The 
majority of TVs available only accepts YPbPr.
My last circuit is a little different from that one on the B-Y/R-Y part. 
That one leaves the colors too much "washed out".
Below it's my last experiment that I tested in one of mine CP-400. The 
first board version of the CP-400 already has Y, B-Y, R-Y and BIAS 
directly available near the monitor connector, leaving it as good choice 
for testing.

https://picasaweb.google.com/109345699838454178536/CP400ModeloI16K#6072064962928262546

https://picasaweb.google.com/109345699838454178536/CP400ModeloI16K#6072064906406443330

https://picasaweb.google.com/109345699838454178536/CP400ModeloI16K#6072064850863548578

https://picasaweb.google.com/109345699838454178536/CP400ModeloI16K#6072064887988193234

https://picasaweb.google.com/109345699838454178536/CP400ModeloI16K#6072064951715238050

As you see the color are too much saturated and I need to add trimpots 
to regulate it properly, but unfortunately the TV that I made those 
tests died recently and it was the only one that accepted YCbCr here at 
home...

Daniel


On 21/04/2015 18:32, Zippster wrote:
> That circuit won’t drive component inputs on a standard television properly.
> I tried it on several quite a while back when I first started playing with the 6847.
>
> You can get a good Luma only display from the Y portion of the circuit,
> but the color difference signals are completely off as far as level.
> They also aren’t terminated correctly.
>
> Someone should work up a circuit for this though, component out would be worth
> having.  I’d suggest using op-amps, ac coupling the signal into and out of the amp circuit.
>
> - Ed
>
>
>
>
>> On Apr 21, 2015, at 3:32 PM, Joe Grubbs <jsgrubbs at hotmail.com> wrote:
>>
>> Suweet! Thanks!
>>
>>
>>
>>> Date: Tue, 21 Apr 2015 16:15:52 -0400
>>> From: linville at tuxdriver.com
>>> To: coco at maltedmedia.com
>>> Subject: Re: [Coco] MC6847 + Component video
>>>
>>> On Tue, Apr 21, 2015 at 04:04:18PM -0400, Joe Grubbs wrote:
>>>> The 6847 datasheet implies that one could connect it a monitor/television with component (Y-BY-RY) inputs via some kind of driver or buffer. Has anyone ever tried this? If so, is there a schematic for a driver/buffer that works well?
>>> Daniel Campos has such a circuit.
>>>
>>> https://twitter.com/RetroCanada76/status/299203476859260929/photo/1
>>>
>>> -- 
>>> John W. Linville		Someday the world will need a hero, and you
>>> linville at tuxdriver.com			might be all we have.  Be ready.
>>>
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