Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcrware!mwca!bill
From: bill@mwca.UUCP (Bill Sheppard)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: Display blues
Message-ID: <1741@mwca.UUCP>
Date: 12 Nov 90 19:13:48 GMT
References: <1737@mwca.UUCP>
Organization: Microware Systems Corp., Santa Clara, CA
Lines: 35

In article <1737@mwca.UUCP> bill@mwca.UUCP (Bill Sheppard) writes:
>My mono display has been exhibiting weirdness lately - any ideas would be
>welcome:
>
>The display starts flickering where vertical lines will be drawn approximately
>every eight characters, heavier at the top of the screen, lighter towards the
>bottom...

and other horrible symptoms...

>My assumption is that this is a monitor problem, not an ST problem...

After receiving mail from several people (thanks!) suggesting both monitor
and ST problems, my further experimentation has indicated a _monitor_
problem - I've made a cable for use with a Sony 1302 multisync in mono mode
and there is no indication of trouble.

One suggestion was that the circuitry in the monitor which differentiates
between low and high (light and dark) may be getting flaky - this sounds
reasonable based on what I see. It is interesting that vertical lines were
seen on exact character boundaries, though perhaps there is a slight variation
in signal level at these points which is enough to affect the monitor. At any
rate, I'll be taking it in for repair in a few days.

As a side note, the Sony works reasonably well as a mono monitor, though
characters aren't quite as clear as on the SM124 (which makes sense
considering there are three beams for each pixel, as opposed to one on the
mono monitor). I could wire up only R, G, or B, but none of those three
color choices sounds too appealing. There is also some slight bowing of the
screen near the top...
-- 
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#  Bill Sheppard  --  bills@microware.com  --  {uunet,sun}!mcrware!mwca!bill   #
#  Microware Systems Corporation  ---  OS-9: Seven generations beyond __/_!!   #
#######Opinions expressed are my own, though you'd be wise to adopt them!#######