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Lcd backlight doesn't work most of the time.

Last response: in Laptops & Notebooks
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December 12, 2010 6:23:02 PM

The backlight of my notebooks lcd screen doesn't turn on. I have read lots of answers on google and different forums, haven't found a solution yet. I am out of ideas, maybe you aren't.

Most of the time backlight does not work, then maybe one time, out of fifty, it is working after powering on the notebook. When it is working, I can move the lid (open, close), shake computer or whatever - it is working like normally it should. Then after shutdown, it does not come back on.

I have replaced the inverter. Tested the screen by connecting it to another notebooks inverter - backlight is working properly. I've also opened up the computer and checked if the switch isn't stuck.
December 13, 2010 3:45:57 PM

What happens when you connect your netbook to an external monitor?
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December 15, 2010 6:26:23 AM

External monitor shows the picture.
Seems like there is a problem with lcd cable.
beanoslim said:
What happens when you connect your netbook to an external monitor?

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December 15, 2010 9:42:43 AM

Have you tried running with the screen seperate from the unit, I mean the cables free and the screen laid flat.

Just wondering if you are nipping a cable or a very minor short is occuring.

If it works ok, try squeezing along the cable while its on to see if it goes off, then you know its a cable prob.
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December 16, 2010 8:38:54 AM

tried squeezing the cable with no luck. I tested the cable with multimeter, seems there are no connection from plug to pin 4 and 5 (8pin coming to inverter). Those are brightness and switch control signals, i suppose.

beanoslim said:
Have you tried running with the screen seperate from the unit, I mean the cables free and the screen laid flat.

Just wondering if you are nipping a cable or a very minor short is occuring.

If it works ok, try squeezing along the cable while its on to see if it goes off, then you know its a cable prob.

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December 16, 2010 10:11:25 AM

Like you say sounds like a faulty cable if it outputs display to an external monitor with no problems.

Still thats better than an lcd replacement. :p 
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December 27, 2010 7:57:23 PM

Ok, i fixed the cable. Backlight switched on, all was ok. And then, suddenly it didn't switch on again, after power on. After it, again, switched on and working normally for a while now. Then I noticed on a white background slight flickering of a backlight in lower left corner. Is it the lamp now?
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December 27, 2010 8:32:36 PM

If everything is securely plugged in and nothing is being pinched then it doesn't look good, downer :( 
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April 28, 2011 10:22:09 AM

beanoslim said:
If everything is securely plugged in and nothing is being pinched then it doesn't look good, downer :( 


Yes, downer. It was both the lamp and the cable, changed the lamp and made workaround with a single wire. For a while all worked nicely, but then new lamp failed again. I thought maybe it's because I wasn't too careful when replacing, could be that a part or one end of the lamp was pressing against plastic or maybe metal case causing too much heat(?). Then I got another lamp and broke it while replacing. That was it. I had to give up on this, as it was already too much time & money spent.

Lesson learned. Do not replace lamps on a notebook screens, get a new screen instead if possible.
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April 28, 2011 10:24:12 AM

Best answer selected by delis.
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