[Coco] CoCo2 black and gray video only -- need help!

[Gene Heskett]

On Saturday 23 October 2021 00:22:41 Dave Philipsen wrote:

> The colorburst frequency of 3.579545 is derived from the 14.31818
> crystal (14.31818 / 4 = 3.579545). I’m pretty sure any frequencies
> generated in that RF modulator are solely for generating the VHF
> carrier and associated signals for the TV. I assume you’re getting a
> clean picture on channel 3 or 4. The problem of it being in black &
> white is related to the colorburst which is on each video line. All of
> that timing is taking place in the SAM and VDG. And I don’t believe
> the VDG itself is very picky about the exact frequency it runs at. I
> have seen spec sheets speaking of using a 16 MHz crystal so it can
> create video at that frequency albeit not according to the NTSC color
> standard.

16 would be for PAL versions I think.

> Dave

Cheers, Gene Heskett.
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