Re: Compaq display problem.

Roy wrote:
"Roy" <Roy.Preston@xxxxxxxxxxx> wrote in message news:492e4641$1_1@xxxxxxxxxxxxxxxxxxxxxxxxx
"cliff wright" <c.c.wright@xxxxxxxxxxxxxxx> wrote in message news:4925303a$1@xxxxxxxxxxxxxxx
Has anyone come across a compaq 3000 series with a display that appears "washed out" just like a CRT display with the contrast turned away down.
I have one here that is fine except for this annoying problem. It is JUST possible to see text on the screen at a critical angle, but it is quite useless practically. Seems a pity to throw out an otherwise Ok laptop, I even got the bad Power connector fixed too!
Any ideas welcome.
Cliff Wright new zealand.
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 it.
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.
Good Luck!
Roy, Preston UK
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.
Roy


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 order
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.
mike
.

Relevant Pages

  • Yamaha YPG-625 display looks washed out (Keywords: YPG625 , YPG 625)
    ... I have a Yamaha YPG 625 Keyboard, ... display looks "washed out" and has a good contrast only when seen at ... this display is really annoying. ...
    (rec.music.makers.piano)
  • Re: Casio Fx-991ES = Absolutely non CAS
    ... Probably one of the worst display I ever used. ... And the contrast of the characters draft on the keyboard is bad, ...
    (comp.sys.hp48)
  • Re: Verifying calibrated gamma
    ... 300:1 and on a very good display 500:1 measured as Sequential contrast, ... Black measurement / Full white measurement. ... Director of Display and Capture Technologies ... should be nominally 1% of the full scale luminance: ...
    (sci.engr.color)
  • Re: All Office Programs Open in Low Resolution
    ... Contrast display with the keyboard shortcut ... Toggle the Windows Theme and color schemes in Windows XP ... The display settings in Control Panel are set to high resolution and all ...
    (microsoft.public.office.misc)
  • Re: TFT contrast problem
    ... I'm trying to interface Casio 3,5" TFT display to ... When bar width is increased contrast is bad ... The configuration utility was not able to ...
    (comp.arch.embedded)