Re: Apple Hi-Res RGB

[rubywand@aol.com (RUBYWAND)]

In article <4mce59$hn4@atlantis.atlantis.actrix.gen.nz>,
dempson@atlantis.actrix.gen.nz (David Empson) writes:

>
>You are out of luck - the Apple Hi-res RGB monitor (13") does not work
>properly on the IIgs.  What you are seeing is the monitor's attempt to
>synchronize with the video signal produced by the IIgs, which is at
>too low a scan frequency for the monitor to handle.
>
>
>Hm... a thought just occurred to me: how hard would it be to make an
>external box which plugged into the IIgs RGB port, sampled each video
>line and regenerated it twice, at double the scan frequency?  This
>would allow the IIgs to work with most modern analog RGB monitors.
>....
>

     Based upon a comparison of standard VGA and GS monitor inputs, the
solution may be fairly simple. VGA monitors would be happy enough with
GS's 60Hz Vertical Sync.

     The main problem seems to be that GS uses a composite Sync while VGA
uses separate Vertical and Horizontal Sync signals. A IIgs-to-VGA
converter box could handle plug conversion and include a sync seperator
plus any signal level adjustments which might be required.
    



Rubywand