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- Re: Compaq display problem.
November 27, 2008, 7:21 am
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Whilst the 3000 can hardly be described as a laptop, it is indeed
worth saving. Is it possible to try plugging in an external monitor?
If this works ok then the chances are its either the invertor or CCFL
tube. The inverter is definately the most likely cause, these can be
obtained quite cheaply on ebay or some such. Not a major job to
change, it lives behind the screen bezel at the bottom. The screws for
the bezel are concealed behind the small rubber plugs dotted around
You may even be able to pick up a complete screen/lid assembly quite
cheaply. Again, very easy to replace. Two screws on the bottom hold
the back top cover behind the keyboard on. Remove them and gently pry
just between the keyboard at one end and the cover should pop up. (Be
careful!) unplug the little white plug that attaches the screen to the
motherboard and remove the lid/screen complete by undoing four screws
at the hinges. I have had several of these where the inverter has been
restored by resoldering all of the connections.
Roy, Preston UK
Re: Compaq display problem.
Forgot to add that if your 3000 is equipped with built in wireless its
a little more complicated - the grey and black antennae wires snake
their way from the lid/display to the wireless card that is tucked
away under the keyboard. You have to undo the four screws at the rear
of the keyboard and swing the keyboard towards you taking care not to
damage/dislodge the film connector loom. The grey and black leads are
just attached to the wireless card by tiny press studs.
Re: Compaq display problem.
Your description is a little vague. You didn't say anything about loss
of brightness...only contrast.
If the display is as bright as you think it should be and uniformly
lit, your inverter and backlights are probably ok.
If it's not a TFT, there should be a contrast adjustment somewhere.
But it very likely is a TFT and there's no particular mechanism to cause the
contrast to go low. You might postulate some weird loss of all the high
data bits, but it's very unlikely that the screen would stay white
in such a situation. There may be a bias voltage that's gone missing
from the row/column drivers. But it seems to be generated on the display.
Just for fun, take out your polarized sunglasses and look at the screen.
At one time, people thought it cool to remove the front polarizer
and use polarized glasses so the guy sitting next to you on the airplane
couldn't read your screen.
I dug thru some TFT data sheets looking for clues. None that I looked at
had any means to adjust the contrast on the TFT. But I did find one with a
gamma correction circuit. That got me to remember that some windows display
drivers have the ability to adjust the gamma of the display. If that's
set too low, you'll get very low contrast. Worth a look.