[Coco] 6847 Video (newbie question)

[Didier Derny]

Hi Luis,

I saw some schematics for svideo with the coco but I can't remember where

I started with the gbs simply because the composite video of my coco 2 
is so bad
that it's almost unusable  (and composite video of the coco 3 is worse)

but for the coco3 I'll use your solution :)

--
didier


On 06/11/2014 21:58, Luis Antoniosi (CoCoDemus) wrote:
> Yep diddier,
>
> I was to mention that S-Video is much more available (even some 200x
> monitors still have it). And use less cables and don't need this crappy gbs
> board.
>
> The S-video circuit is much more simpler and require less color tuning.
>
>
> Luis Felipe Antoniosi
>
>
>
> On Thu, Nov 6, 2014 at 3:45 PM, didier derny <didier at aida.org> wrote:
>
>> This is the result:
>>
>> http://6809.eu/t1.jpg
>>
>> another test:
>>
>> http://6809.eu/t2.jpg
>> (colors better on the real screen)
>>
>> Btw I don’t have a coco3 but a coco2
>>
>> I've not soldered floating wire to the 6847
>> But I've soldered a socket (with pins 1,3,8,10,12,13,14 cut)
>> [if I remove my connector, the tv modulator is still working]
>>
>> Then on this improvised connector I connect either
>> The composite or the ypbpr interface.
>>
>> The ypbpr interface is just a bunch of wires
>> Connected to a small breadboard
>>
>> http://6809.eu/if.jpg
>>
>> now that I have a result I'll rebuilt it on a larger breadboard
>> with some adjustable resistor to try to improve the result
>>
>> for example, the black is not really black
>>
>> then I'll move to a real pcb
>>
>>
>>
>> -----Message d'origine-----
>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Daniel
>> Campos
>> Envoyé : mercredi 5 novembre 2014 22:47
>> À : CoCoList for Color Computer Enthusiasts
>> Objet : Re: [Coco] 6847 Video (newbie question)
>>
>> Very good already! But please do the command bellow and take a picture,
>> please.
>>
>> FOR I=32 TO 255:? CHR$(I);:NEXT
>>
>> Daniel
>>
>> Em 05/11/2014 19:44, didier derny escreveu:
>>> I modified the value of some resistors, I get a better result
>>>
>>> This is what I get:
>>> http://6809.eu/ypbpr3.jpg
>>>
>>> for reference the composite:  (it's just ugly) :(
>>> http://6809.eu/composite.jpg
>>>
>>>
>>> Modification made to Luis schematics:
>>>
>>> 150 ohms resistor between emitter of the first transistor and GND
>> replaced by 330 ohms
>>> 75  ohms resistor Cb out  and Cr out    replace by 37.5 ohms  (2
>> resistors 75 ohms in parallel)
>>> All le settings of the GBS 8220 are set to default
>>>
>>>
>>> --
>>> didier
>>>
>>> -----Message d'origine-----
>>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de didier
>>> derny Envoyé : mercredi 5 novembre 2014 21:45 À : 'CoCoList for Color
>>> Computer Enthusiasts'
>>> Objet : Re: [Coco] 6847 Video (newbie question)
>>>
>>> In fact it was a problem with the breadboard (a stupid bad contact)
>>>
>>> http://6809.eu/ypbpr2.jpg
>>>
>>> I'll try to find a color test...
>>>
>>> I find the black really good compared to composite With the composite
>>> the letter S looks a little bit like 8
>>>
>>> I don’t find the colors ok, "too clear"
>>> (looks better on the image, that it really is)
>>>
>>> --
>>> Didier
>>>
>>>
>>>
>>> -----Message d'origine-----
>>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Luis
>>> Antoniosi (CoCoDemus) Envoyé : mardi 4 novembre 2014 23:15 À :
>>> CoCoList for Color Computer Enthusiasts Objet : Re: [Coco] 6847 Video
>>> (newbie question)
>>>
>>> Inverted transistor ? Did you check the datasheet ? They change EBC pins
>> from vendor to vendor.
>>>
>>> Luis Felipe Antoniosi
>>>
>>>
>>>
>>> On Tue, Nov 4, 2014 at 5:11 PM, didier derny <didier at aida.org> wrote:
>>>
>>>> This is what I get, I have an image but obviously I have a problem
>>>>
>>>> This is the 3 signals   Y + PB + PR
>>>> http://6809.eu/ypbpr.jpg
>>>>
>>>> I tried with only Y connected  (I expected a black and white image)
>>>> http://6809.eu/y.jpg
>>>>
>>>> It's connected to a GBS 8220
>>>>
>>>> --
>>>> Didier
>>>>
>>>>
>>>>
>>>> -----Message d'origine-----
>>>> De : Coco [mailto:coco-bounces at maltedmedia.com] De la part de Luis
>>>> Antoniosi
>>>> (CoCoDemus)
>>>> Envoyé : vendredi 31 octobre 2014 22:04 À : CoCoList for Color
>>>> Computer Enthusiasts Objet : Re: [Coco] 6847 Video (newbie question)
>>>>
>>>> It works, but you need to make a driver:
>>>>
>>>> https://pbs.twimg.com/media/BCb7-hoCEAAJm22.jpg:large
>>>>
>>>> When I used my it suffered from severe jumps time to time. maybe you
>>>> have better luck and a better board.
>>>>
>>>>
>>>> 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
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
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>>>>> Coco at maltedmedia.com
>>>>> https://pairlist5.pair.net/mailman/listinfo/coco
>>>>>
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