[Coco] Coco 3 composite bad / usable / unusable

[Didier Derny]

Hi received my coco 3

I got the following results:  (composite video)

32 columns, image awful but readable
40 columns, better quality than 32 columns, the is not is not perfect, 
easily readable
80 columns, unusable

I got almost the same result with  3 different adapters

ntsc -> hdmi then  hdmi to vga     (gives me acceptable result with 
apple 2, but far from good)
ntsc -> htmi  then  hdmi to vga    (gives me  a really good result with 
old commodore, and a mo5, not working with apple)
ntsc -> vga   (hd game box)           (good result with commodore not 
working with apple)

all gives the same result with the coco 3

on my tv  (via composite) the quality of the image is slightly better...


is this result normal ?
anything I can do to improve the result ?

the coco has the warranty sticker over the screw hole
so it was not modified

I guess I have to make a cable for rgb and try it ?

--
didier