15 Apr
2013
15 Apr
'13
7:43 a.m.
On Mon, Apr 15, 2013 at 7:56 AM, Kevin Parker <trash80 at internode.on.net>wrote:
Hi Matt - while I really liked watching what you did
and watching it fire
up
I'm interested in the RGB to VGA converter you used as I have quite a few
legacy machines but a shortage of old monitors but no shortage of VGA
screens.
Kevin,
The CoCo uses a fairly simple signal that's similar to CGA in many
respects. The main issue I had was the fact that it uses separate H and V
sync signals instead of a composite sync. The board I purchased and that
you see in the video is similar to this (
http://www.ebay.com/itm/RGB-CGA-EGA-YUV-to-VGA-Arcade-HD-Video-Converter-Bo…)361).
While it supports separate sync signals, it won't capture at 15kHz.
So I found a schematic at
http://www.epanorama.net/circuits/vga2rgbs.htmlon how to build a
simple composite sync, fed that into the converter board,
and it worked like a champ. That little board isn't visible in the video,
but I home etched it. Both conversion boards run off of a small 5v
switching wall wart.
Total cost was about $30 and a little time and soldering.
Hope that helps.
-Matt