Installation problem

Karl Hegbloom hegbloom at
Thu Jun 16 01:48:37 UTC 2005

On Mon, 2005-06-13 at 15:09 +0100, John French wrote:
> All went apparently well, all the usual packages were installed (as
> far as I could tell), until the point at which I expected ubuntu to
> start. At that point my monitor showed a message, "Input signal out of
> range", and nothing further happened. This gave me no opportunity to
> correct anything. 

You're lucky you have a new monitor that protects itself.  A few years
ago, I had an older CRT that started to whine, like a tea-pot, and then
a waft of smoke came out of the top grills, as it winked out forever.  I
was over-driving it.  Newer monitors have protection logic circuitry
that prevents this from happening.

As others have said, you need to reconfigure the 'xserver-xorg' package.
You may need the '-p low' option to get all the questions to show up.
After you run it, you must run 'dexconf' to get the changes written to
the conffile, IIRC.  If it does not write the /etc/X11/xorg.conf then,
try moving the old one aside, and then run 'dexconf' again.  dexconf
reads the values you input using 'dpkg-reconfigure -plow xserver-xorg'
and uses them to write the new xorg.conf.

If you don't have a manual that contains the HorizSync and VertRefresh,
you can usually find it by using Google for the monitor brand and model
number.  Often enough, you can simply use the "medium" option, and
select the monitor resolution from the list.  For an LCD, you probably
need the slowest scan frequency for that resolution; I'm guessing.

It is also possible that all you need to do is comment off the
'HorizSync' and 'VertRefresh' in the xorg.conf, and allow the X server
to perform DDC detection for you.  That works for most "plug and play"
monitors, that is, most new ones.  It uses a simple serial protocol of
some kind to read information from the monitor itself, over the video
cable.  I've seen it fail on older monitors, but brand new ones SHOULD
work fine that way.

You may need to run the 'dpkg-reconfigure' + 'dexconf' to get the
resolution you want... near the last question it asks... and then edit
the xorg.conf and comment off the HorizSync and VertRefresh.

If it starts to whistle, hit the power switch quickly.  Don't trust DDC
on monitors older than about 3 to 5 years... (I'm guessing).

Karl Hegbloom <hegbloom at>

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