I think PC Tech means "You might HAVE blown the back lights"
Actually, I interpret your statement "While changed the voltage from 19v to 24v,the display become dark" to mean that somehow you tried to run the computer off a supply providing 24V, instead of the correct unit which supplies 19V.
If this is the case, you could have done all sorts of damage.
I just wonder why you did it.
Allan, December 2010
