Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!linac!att!ucbvax!ecs.oxford.ac.uk!u87rpb
From: u87rpb@ecs.oxford.ac.uk
Newsgroups: comp.sys.atari.st.tech
Subject: Mono monitor signal hacking
Message-ID: <9103222256.AA06374@uk.ac.oxford.ecs.booth16.ecs>
Date: 22 Mar 91 22:56:09 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 24

Hi there, does anybody have any idea what might be involved
in trying to get a mono monitor to think it's a colour
monitor (ie, to display low and med-res screens in
greyscale) in *hardware* ?

As far as I can tell with the RGB outputs, it would probably
be a question of simply hooking up a resistor net with the
right `weightings' to generate a mono intensity signal. [At
a guess, although I haven't put a scope on them, I imagine
that the RGB and Mono lines are simple intensity signals
with no additional sync information at all].

The major problem as far as I can tell would be the sync
signals. What would happen if I tried driving an SM124 with
a 50 Hz frame frequency (or 60 Hz, if neccesary)? I guess
that I'll either get no picture at all, or get something
like a two-thirds height picture.

Thanks,
Ray.

p.s. I modified my picture size last week after reading
reports about people doing this on comp.sys.atari.st.tech,
reckon I've got another 20% of useful screen area now...