Re: Apple Hi-Res RGB

[chrisw@eagle.ais.net (Chris Wicklein)]

RUBYWAND (rubywand@aol.com) wrote:

:      "Bzzzzt!" Bad news, indeed. It is a shame if the Mac monitor requires
: a minimum 31.5kHz Horizontal Sync.

:       It would be interesting to test some standard VGA monitors and see
: if any can sync at 15.75kHz. If not, then some kind of frame-grabber with

	My Amiga powers up with a 15.75KHz display which is unviewable on 
my SVGA monitor.  I'd be surprised if you could find a VGA type monitor 
that could sync below 25KHz.  If you're in the mood to fiddle and break 
something, try experimenting with a monitor on the Amiga, which supports 
true NTSC, 15KHz composite video, and VGA displays through editable drivers.

: the necessary VGA outputs may be the IIgs-to-VGA solution-- not a very
: elegant one and likely to be pretty expensive.

	This reminds me of a IIGS slot add-in board that Sequential 
Systems is selling...

:       Some line-grabbing scheme like David's might get the job done at
: much less cost. The hardware input does A/D and stuffs line info into a
: LIFO stack. The hardware output sends an 'off' line and then begins to
: pull line info off the stack, do D/A and send it. After 200 "off" and 200
: displayed lines, the hardware repeats the process except that displayed
: lines appear where 'off' lines were sent on the last pass. You would be
: interlacing two 200-line frames but, at 30Hz, it would look like one
: 400-line frame.  

:      Another non-IIgs monitor candidate is the RGB monitor used with the
: Commodore 128. These probably sync fine at 15kHz and, perhaps with minor
: plug conversion, should work on a IIgs.
:     

	To bring up that other computer again, older Amiga RGB monitors 
run at 15KHz, and have stereo speakers too.  I am partial to a SS board 
and a standard SVGA monitor because for an investment of $500 you would have:

o standard IIGS video scan-doubled onto a 15" high resolution color monitor
o new optional video modes of 800x600x256 and higher
o a monitor that would be useful on other computers

	Since I already own a SVGA monitor, I'm solving my IIGS display 
problems for $189.

: Rubywand

--
Chris Wicklein - EMAIL: chrisw@ais.net - URL: http://www.cl.ais.net/chrisw 
"He strode down the hill amid the tumult of suddenrisen vapours of 
 wounded pride and fallen hope and baffled desire." -- James Joyce, POA