just blew up my 17" monitor

Mike A. Harris mharris at redhat.com
Sun Nov 9 13:51:09 UTC 2003

On Sat, 8 Nov 2003, Magtanggol Kalingasan wrote:

>I don't know if its fedora's or my monitor's problem, my monitor
>was unprobed so i entered the Hsync and Vsync from the manual,
>the installation(fresh install) went smooth. After the
>installation i was prompted to reboot, the graphical boot-up was
>nice, i was prompted to create a regular user and all those post
>install stuff. Then I logged in, saw the GNOME start up. I was
>begining to navigate the menus when the monitor's view shrunk,
>then kapooooffff!!!! Then I smelled some burned plastic/stuff
>coming from my monitor.
>Kinda weird, i used the same Hsync and Vsync on this same
>machine with the RH9 install. is it FC1's fault? or bad
>hardware? any similar experience here?

Modern CRTs have built in protection circuitry which autodetect 
out of range frequencies and either power down the display when 
bad frequencies are present, or they switch the video input off, 
and display a user friendly "Out of range signal" message on 
screen, perhaps with more details.

Older monitors that do not have this protection built into them, 
can be physically destroyed if they are sent video signals which 
they can not handle.

The best thing to do is to let monitors autodetect via DDC 
probing and use the autodetected values.  If the display does not 
support DDC, or if DDC isn't available for any other reason 
(there are several other reasons why DDC might not be available), 
then you should manually select your monitor from the list of 
monitors.  You should only punch in your horiz/vert rates 
manually if you have no other option, and you should make 
absolutely sure that the numbers are 100% correct, especially if 
it is an older monitor without 'out of range' protection.

It is also possible to destroy LCD panels by providing incorrect
video signal information.  Even many modern LCDs can be destroyed
in this manner if programmed incorrectly.  If you ever configure
an LCD and see bright white "blooming" on the display, power it
off immediately.

Sounds like you've let the smoke out of this one....

Mike A. Harris     ftp://people.redhat.com/mharris
OS Systems Engineer - XFree86 maintainer - Red Hat

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