[Coco] 6847 Video (newbie question)

Retro Canada retrocanada76 at gmail.com
Wed Nov 5 16:52:22 EST 2014


now test games like lunar rover and f-16 and see how bad this board perform when scrolling :/

also type fast or print a long basic listing. Looks like there is something wrong ...

On Nov 5, 2014, at 4:44 PM, "didier derny" <didier at aida.org> wrote:

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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> 
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