Did more tests and also a small video:
[url='
http://www.youtube.com/watch?v=Wmayyx1C6DU']Rampage Dongle Test[/url]
And two pictures:
-> Original image from my old notebook
-> Inverted image on external TFT
I have a theory about the stripes that are strongly visible when the image is negative.
The original image has a black frame as you can see here:
The picture itself is inverted all the way correct, cause every pixel has a value. But the black frame isn't inverted right, only the parts where the picture is drawn is right.
What I marked red isn't inverted because the color is "blank" and has no value what the Dongle could convert. This is at least what I think and it makes sense to me.
Luckily this is no big problem, the 3dfx Rampage inverts the whole image to 100%, so the Dongle does always have the information/values it needs. You can also see this when you look at my video. Here I inverted the image by software (Powerstrip -> invertes and writes the image directly in the DAC) so that the Dongle does what it should at least do.
@Tim: Hank did design and build it. Heh did state that my design is correct. All I don't know are the used transistors.
Sirta sold his card with everything else. I know the person who owns the board and the dongle, but I don't want to name the person in public. Don't know if the person would want it. But the person is known by the 3dfx Community