[Coco] Will this build-your-own s-video board work for CoCo 3?
snhirsch at gmail.com
Wed Mar 9 07:25:20 EST 2011
On Tue, 8 Mar 2011, Steve Bjork wrote:
> A simple Google search came up with this from CoCo3.com...
> In the case of the Amiga 1084, it requires combined negative sync in
> analog RGB mode, so you need to take the separate positive H and V sync
> from the CoCo and feed them into the inputs of a a NOR gate a 74LS02
> has four such on it, and use the output of that NOR gate to provide
> sync to the Commodore monitor.
Here's a nice writeup with several schematics for an H / V --> H+V
I threw together the version for "TTL level sync", fed that into an
el-cheapo Chinese CGA to VGA board (< $40 on eBay) and was able to get
decent display of CoCo 3 video on a Dell LCD monitor.
That said, Roy's unit does a bit better job at eliminating fringing
effects. I tried building a low pass filter per his recommendation, but
it did not seem to help - probably because the input impedence of my
converter is different from his.
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