Re: pin driver difference between early/later VIC-II?

On 3/4/21 11:13 AM, Francesco Messineo wrote:
[...]
> Changing R10 to 120 ohms gave a quite normal "bright" image and also
> the chroma lagging effect
> of the 6567R56A appears reduced but still noticeable.
> Since I don't have any other NTSC (newer) board nor any other 6567
> chip, I wanted to know if my
> particular R56A is defective or if there's a reason for this effect,
> maybe different driver stage on the output pins?

There appears to be some kind of delay circuit, using chains of inverters, in 
the VIC-II for the luma output, maybe that changed between R56A and newer 
versions. It could be interesting to compare die shots, if there are any. I 
haven't found any decent quality die shots for any 6567 revision, though.

Cheers
Michiel