Re: Is it at all possible?

From: Gerrit Heitsch <>
Date: Mon, 20 Feb 2017 08:19:57 +0100
Message-ID: <>
On 02/19/2017 11:47 PM, HÁRSFALVI Levente wrote:
> Another addendum: Marko once measured the luma levels of different
> VIC-II chips in the same C64 motherboard,
>  . I don't know how well the data practically holds, since the
> measurements have been done without using a standard 75 ohm load; yet,
> one thing seems to be sure: there are slight differences between
> different VIC-II chip revisions in the luma levels they produce. Maybe
> part of what I've seen has been a result of that. I can't speak of the
> other symptoms, I didn't make measurements myself.

We have to remember that VIC is a bit of a mixed signal chip, it is 
mostly digital, but also produces analog signals. I take it as a given 
that there will be slight differences between VICs of the same revision, 
even if they come from the same wafer, let alone from different 
production runs where the process was tweaked over time.

So measuring luma levels only counts if you have multiple VICs of each 
revision you can compare against each other.


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