Re: Apple RGB monitor

[spec@vax2.concordia.ca (Mitchell Spector)]

In article Maureen <mo@connect.ab.ca> writes...

>I have an Apple RGB monitor which I use with an Apple IIGS.  Could
>someone tell me if I could use this same monitor with a Mac, and if so
>which one?  Thanks in advance.

    Generally speaking it is not compatible with any Macintosh, due
to the fact the horizontial scanning frequency is incompatible (the
AppleColor RGB works at 15.75 kHz--NTSC rate, compared with 30+ kHz
used and required by the Macintosh and PC's with VGA/SVGA output).

    There is a rare exception, if you have the 'High Resolution
Display Video Card' (Apple part no. 820-0185) it will connect
directly to the monitor and adjust its frequency to match. This
card works only in NuBus slotted Macintoshes, so that leaves you
with support for mostly the Macintosh II line. Even so, I would
recommend against this option for a couple of reasons: 1) The dot
pitch is quite low (0.37mm) which will make things appear a bit
blurry and difficult to make out detail. 2) You have to operate
it in interlaced mode, meaning it will flicker noticably and will
cause eye strain in a few short minutes or less. 3) The maximum
resolution it supports, in interlace, is 640x400. Most Macs use
a slightly higher vertical resolution, meaning part of the image
will get chopped off. 4) The maximum refresh rate supported is
60 Hz, which causes more eye strain because it flickers out of
the corner of your eye and is more glaring (this may not affect 
you though, it is _very_ common for Macs to use low refresh rates 
like 67 Hz, which also flickers but I guess Mac users are able
to deal with it. People outside N.A. deal with 50 Hz...yikes! :).

    Bottom line--unless you have a NuBus slotted Macintosh and
that above video card (and don't mind if your display is blurry,
partly cut and potentially causes eye-strain and headaces) then
your better off finding a modern display, or at least one made
for the Macintosh. :-) You can use a PC SVGA display, with a
small and fairly inexpensive (sometimes free) video adapter as
well, which gives you a wider option for picking monitors.

Mitchell Spector
spec@vax2.concordia.ca