Color Classic II VGA mod

[ttb]

I have a Color Classic that I modified with the standard 68.4V VGA mod, as documented on https://powercc.org/640x480/ and elsewhere. This machine works perfectly with an LC575 logic board. I also have a Color Classic II and I'd like to standardize both with a VGA res. When I swap the CC2 logic board into the VGA-modded CC, the monitor displays a rolling 640x480 picture.

I would have thought the stock CC2 logic board would be able to handle VGA since it's basically an LC550 logic board. Are there differences between a real CC2 logic board and a LC550 logic board which might prevent the former from working out of the box on a VGA-modded CC?

 

[Arbee]

You probably need to also tweak the monitor sense pins to indicate a 13" 640x480 monitor instead of the 12" 512x384 mode. I don't have any information about how that works on a real board though.

 

[ttb]

Thanks! I did that on the analog board so I believe the correct coding should be passed down to the logic board. The fact that it registers as 640x480 (though with a rolling image) makes me think it sees the sense lines in some capacity.