[Coco] 6847 Video (newbie question)

[Brett Gordon]

the color signals are knocked down .6 Volts because of the emitter
followers.. that might explain why the colors are fugded up.

On Sat, Nov 1, 2014 at 1:20 PM, Zippster <zippster278 at gmail.com> wrote:
> The Y signal has to be inverted.
>
> BTW this circuit won’t drive a component input on a television. (the ones I’ve tried anyway).
> Well, luma gets decoded, but the levels don’t seem to match up for color (for modes
> other than the text display on startup at least).
>
> Interesting to hear it works with a GBS8220.
>
> - Ed
>
>> On Nov 1, 2014, at 9:34 AM, Brett Gordon <beretta42 at gmail.com> wrote:
>>
>> I'm not an EE, but aren't CbOut and CrOut just emitter-followers?  I
>> don't think they need ground. The current sink is the "grounding".  I
>> Wonder why the "Y" has two transistors stuck on it.   One voltage
>> inverter amp followed up by anther emitter follower (current amp).   Y
>> must be inverted?
>>
>> B
>>
>> On Sat, Nov 1, 2014 at 9:48 AM, Retro Canada <retrocanada76 at gmail.com> wrote:
>>> don't know about the pulldowns, i got the scheme from Daniel.
>>>
>>> the image is pristine.
>>>
>>> On Nov 1, 2014, at 6:19 AM, Tormod Volden <lists.tormod at gmail.com> wrote:
>>>
>>> On Fri, Oct 31, 2014 at 10:03 PM, Luis Antoniosi (CoCoDemus)
>>> <retrocanada76 at gmail.com> wrote:
>>>> It works, but you need to make a driver:
>>>>
>>>> https://pbs.twimg.com/media/BCb7-hoCEAAJm22.jpg:large
>>>
>>> Shouldn't the CbOut and CrOut drivers have a resistor from emitter to ground?
>>>
>>>>
>>>> When I used my it suffered from severe jumps time to time. maybe you have
>>>> better luck and a better board.
>>>
>>> Apart from the jumps, what does it look like? Perfectly sharp and
>>> stable picture with good colours?
>>>
>>> Regards,
>>> Tormod
>>>
>>>>
>>>>
>>>> Luis Felipe Antoniosi
>>>>
>>>>
>>>>
>>>>> On Fri, Oct 31, 2014 at 3:58 PM, didier derny <didier at aida.org> wrote:
>>>>>
>>>>> I just received a GBS 8220 and I was wondering if the YPBPR entries of the
>>>>> GBS 8220
>>>>>
>>>>> Were compatible with the Y phiA phiB of the 6847 ?
>>>>>
>>>>>
>>>>>
>>>>> Are they the same signal with another name or something different ?
>>>>>
>>>>>
>>>>>
>>>>> Not really understood fig 10 of the 6847 datasheet
>>>>>
>>>>>
>>>>>
>>>>> I often used composite or rgb but never  YPBPR or the signal of the 6847
>>>>>
>>>>>
>>>>>
>>>>> Any idea ?
>>>>>
>>>>>
>>>>>
>>>>> Thanks
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> Didier
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Coco mailing list
>>>>> Coco at maltedmedia.com
>>>>> https://pairlist5.pair.net/mailman/listinfo/coco
>>>>
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>>
>>
>>
>> --
>> Brett M. Gordon,
>> beretta42 at gmail.com
>>
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>
>
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-- 
Brett M. Gordon,
beretta42 at gmail.com