groepaz wrote:It is very very easy to change settings on the C64 modulator so it broadcasts garbage all over various TV channels yet you get a perfectly good picture both on the Y/C output from the 8 pin DIN connector and the RF output.
you must have a very different idea of what a perfectly good picture is than i do then
You don't have a lot of imagination...
Imagine you have set the luma amplitude too high so the modulator does just a little bit of signal clipping when displaying white. If you connect a display device to the 8 pin DIN connector then you'll get a really nice picture, same if you connect to the RF output.
What you can't notice unless you have some top notch RF equipment or scope is this little clipping causes harmonics that you can't see on your TV and/or monitor. These harmonics get into the AM carrier signal mixer and end up completely out of the band of frequency the modulator's output is supposed to stay within. Also, you may end up with a modulation index of more than 100%.
See:
https://en.wikipedia.org/wiki/Amplitude ... tion_index
This causes harmonics to appear on RF unpredictably. So there you have it, just one of myriad ways you can have a perfectly good display while generating garbage at both the input and output of the modulator. This is also true on the VIC-20.
@Ken
I am a business partner with e5frog for PLAnkton solely. What he says concerning other projects does not concern me.
What concerns me is I know how to get a VIC-20 to output a good video signal and I know how to make a very simple S-video mod for a VIC-20, assuming it is adjusted properly in the first place.
Be normal.