[comp.sys.atari.st] question about monochrome monitor

news@uflorida.cis.ufl.EDU (USENET Master) (03/09/89)

leftmost column on the screen are strangely compressed.  Their height
is normal but they are noticeably less wide than normal.   After a few
minutes the effect goes away, and all characters look normal.   Can
anyone tell me what causes this and/or how to avoid it?   Thanks in
advance.

klute%trillian.irb@unido.uucp (Rainer Klute) (03/10/89)

In article <19890@uflorida.cis.ufl.EDU> drc@beach.cis.ufl.edu writes:
>leftmost column on the screen are strangely compressed.  Their height
>is normal but they are noticeably less wide than normal.   After a few
>minutes the effect goes away, and all characters look normal.   Can
>anyone tell me what causes this and/or how to avoid it?   Thanks in
>advance.

I noticed the same effect when my 520ST+ at work got a SH205
harddisk. Whenever I switch on the SH205 before the ST the
effect appears. However, when I switch on the ST before the
harddisk everything looks as it should. So this is what I
am doing:

1. Switch on the ST
2. Wait until the desktop appears
3. Switch on harddisk and floppy
4. Press reset to boot from harddisk

On a ST with built-in floppy this procedure would require a
boot from floppy as you cannot switch it off separatly. Ok, the
whole thing takes a bit longer than a direct harddisk startup
but I couldn't stand that nasty monitor look for hours.

  Rainer Klute                  ----   klute@irb.informatik.uni-dortmund.de
  Universitaet Dortmund, IRB    |)|/   klute@unido.uucp, klute@unido.bitnet
  Postfach 500500               |\|\   ...uunet!mcvax!unido!klute
D-4600 Dortmund 50              ----   Tel.: +49 231 7554663

ftw@masscomp.UUCP (Farrell Woods) (03/12/89)

In article <19890@uflorida.cis.ufl.EDU> drc@beach.cis.ufl.edu writes:
>leftmost column on the screen are strangely compressed.  Their height
>is normal but they are noticeably less wide than normal.   After a few
>minutes the effect goes away, and all characters look normal.   Can
>anyone tell me what causes this and/or how to avoid it?   Thanks in
>advance.

One of two things here.  First, you could have a defective component in
the horizontal sweep circuitry that gets a bit better as it warms up.
One way to track down such beasties is with a can of "freeze mist"
(assuming you want to fix it yourself).

Another thing that perhaps the horizontal centering control is near the
edge of it's useful range.  The way I adjusted mine was this:

Turn the horizontal centering control in one direction until you notice
a bit of folding (characters getting squished).  Back the control off 'til
this just disappears.  Note the position of the control.  Now, turn it the
other direction and watch for the same thing on the other side of the
screen.  Back the control off again and not its new position.  Move the
control exactly between these two points.  If the resulting picture is
not centered on the screen, then use the centering rings on the back of
the yoke to correct it.

This adjustment should be done when the monitor is fully warmed up.  If
you do this adjustment, and the folding is still present when the monitor
is cold, then you'll need to track down the defective component.

I can provide more details if you like; they're a bit tedious, so I hesitate
to post them.  Good luck!



-- 
Farrell T. Woods				Voice:  (508) 392-2471
Concurrent Computer Corporation			Domain: ftw@masscomp.com
1 Technology Way				uucp:   {backbones}!masscomp!ftw
Westford, MA 01886				OS/2:   Half an operating system