On RGB-to-component conversion

[scott@alfter.diespammersdie.us (Scott Alfter)]

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There's been some talk about ways to hook newer monitors to the IIGS lately. 
Having just bought a new monitor with a bunch of different inputs (a Samsung
SyncMaster 215TW), I tried plugging the VGA cable into the GS's RGB output
through a Mac-to-VGA converter dongle.  It was a long shot, so I wasn't too
disappointed that it didn't work.

I then repeated the composite-to-component-Y-input test about which I posted
earlier.  That worked, and the image was a bit more stable than it was on my
TV.

This gave me an excuse to start digging into what would be involved in
connecting a IIGS to a component input.  There's an off-the-shelf option
that might work.  The Audio Authority 9A60 (google for it) is popular among
MythTV users who drive HD monitors with their computers.  It's anywhere from
$100 on up, though.

On the prowl for a cheaper solution, I ran across these pages:

http://archive.avsforum.com/avs-vb/history/topic/193919-1.html
http://www.keohi.com/keohihdtv/interfaces/diytranscoder.html
http://www.keohi.com/keohihdtv/interfaces/diytranscoder_johrhees.html

IIRC, the IIGS uses composite sync instead of separate horizontal & vertical
sync.  I'm guessing that the sync-combiner section (the 74HC00, the two
transistors, and related passives) can be deleted, or maybe replaced with
something much simpler.  The rest is about what you'd figure it would be.

The first link suggests some alternate component choices for the opamps, and
it has some other info.  It looks like between the three of them, there's a
starting point for putting something together that'll work.

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