[Coco] Need help with composite output for CoCo

[Michael Rowen]

I agree that these circuits don't seem to be able to drive modern video inputs. I had the same experience you had - black screen. I had one old CRT monitor that would show up a very dim back on gray. I picked up an old CoCo 1 with a similar circuit in place, same result. Output looks OK on a scope, but not powerful enough to display on a modern LCD TV. The only circuits that seem to work without issue are those based on a an MC1372. I'm sure there are amp designs that work, but haven't been published or fully reverse engineered. There are cheap devices in the $14-$30 range that will convert RF out to VGA. Good Luck!

-Cheers,
Mike







Jamie <reinsj at nbnet.nb.ca> wrote:

>Hi All,
>
>So I'm trying to build a composite video converter for a coco 1 and I can't seem to get it to work.  
>I started with a simple design from Hot CoCo which uses a couple of transistors and a few 
>resistors and then tried Dennis' TV Buff.  
>My question is, should the output work on a modern flat screen LCD TV or do monitors with 
>composite input work differently?  The TV screen responds by going black but I'm not getting any 
>picture at all.
>
>Thanks!
>
>Jamie
>
>
>
>-- 
>Coco mailing list
>Coco at maltedmedia.com
>https://pairlist5.pair.net/mailman/listinfo/coco