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Video
Failure
The
first thing to check in cases of complete video failure is
the power status, as detailed above.
If you can always hear
your laptop fan when you turn on the laptop and now you
can't it's not a video failure, it's a power or main board
failure. The next troubleshooting step is to connect an
external monitor with a standard VGA connector, whether a
CRT or an LCD. If your notebook won't light up the external
monitor, it's extremely likely that either the motherboard
or the internal video adapter (if it's not part of the
main board) has failed. If the video adapter is a discrete
component and you can find a replacement for under $100, it
might be worth gambling on replacing, but it's almost never
cost effective to replace a main board. There is a small
chance that the internal connection to the external video
port has coincidentally failed with the laptop's own video
subsystem, but it's not all that likely.
If the
external monitor works fine, your failure is with the
laptops video subsystem, which is usually contained entirely
in the screen/lid assembly. There is a decent chance that
one of the cable bundles (video signal or power) that run
through the hinges to the video subsystem has failed, so
unless the failure is obvious (cracked screen, fading in a
corner, faint image, bad pixels), you should still open up
the main body of the laptop as well to visually inspect the
connections. The easiest problem to identify is obviously a
cracked LCD, but a slowly increasing number of dead spots or
whole rows or columns on the screen indicates the the actual
LCD assembly is bad. Replacing the LCD is pretty much the
same on most notebooks, Dell has a nice backlight design,
the real challenge is getting the lid open and removing it
without breaking anything.
If
your screen brightness seems to flicker or sometimes is
bright and sometimes almost fades out completely, even then
the unit is plugged into the wall (don't get fooled by power
saver mode), then you probably have a failing inverter or
backlight. Between the two, the inverter is several times
more likely to fail, it plays the role of the solid state
ballast in modern fluorescent lights. The backlight itself
is a CCFL (Cold Cathode Fluorescent Lamp) with a very long
meant time between failure, while whole generations of
inverters have been lemons on some laptop models, you can
easily research your model on Google. I did an illustrated
guide to how to replace an inverter or backlight on a
Toshiba notebook, the process is similar for any laptop.
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