Re: Still trying to get Tandy RGB monitor to work on my GS

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

In article "Sheane Meikle" <action1@telusplanet.net> writes...

>Please someone tell me how to hook it up. I know that I can find a GS
>monitor cheap but I'm way to stuborn to give up without trying, however
>until someone tells me how to make a cross over cable I won't try for fear
>of frying either unit. please help keep me from going insane:) (my wife
>figures I already am)

    Chances are it is not a compatible monitor. The Tandy RGB was
designed for Radio Shack's PC clones, and from what I recall most
of those made were PC/XT compatible. The most common video output
then was CGA or EGA, both of which output digital RGB. The Apple 
IIgs outputs analog RGB and requires a display of that type. If 
you build a properly wired cable a digital display _will_ display
an image, but the colors will be totally wrong.

    If this RGB monitor is VGA/SVGA compatible, it will be totally
incompatible despite the fact this type of display is analog RGB.
These monitors use a higher horizontal scanning frequency (30 kHz 
or higher) which is too fast for the GS to sync to. The GS uses an
NTSC/TV scanning frequency of around 15.75 kHz (Amiga and Atari ST
displays are the same). You would require the Second Sight video
card in this case, but at US$150 it you would be paying more than
the entire computer is worth.

Mitchell Spector
spec@vax2.concordia.ca