Laptop Backlight not working on Dell XPS L702X

Posted on 2013-12-15
Last Modified: 2016-11-23
I knocked my laptop on the floor and now the backlight isn't working.
When I shine a torch on the screen I can see Windows, just there is no backlight to illuminate it.
If I look in the back I can only see one cable going into the LCP panel - on other laptops I have seen two - is there another somewhere I'm not seeing that has come loose?

What are the possible reasons for this problem?
What are the options for fixing it? Do I just need a new LCD Panel?
Question by:purplesoup
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LVL 88

Assisted Solution

rindi earned 333 total points
ID: 39719899
The backlight circuit is usually inside the display, and not the PC, so the cable from the PC to the display can be one cable. It probably splits up inside the display, and possibly also the PC part. So open up your case and the display's cover, and check the connections there.

Author Comment

ID: 39720033
Usually I would think the cause is either the inverter, the cable or the screen, but as this is an LCD screen would it not have an inverter, so it would be either the cable or the screen? Is there a way of finding out which it is?
LVL 88

Accepted Solution

rindi earned 333 total points
ID: 39720061
New laptops don't have an inverter, but they still have some sort of backlight, usually LED backlights. As those don't require high voltage they don't need an inverter. But they still need to be driven. The cable as I mentioned probably splits into at least 2 parts inside the display, one that goes to the panel itself, the other to the backlight part.
LVL 92

Assisted Solution

nobus earned 167 total points
ID: 39720945
here a good site with info on how to test LCD, inverter, and screen :

Author Closing Comment

ID: 39726343
Thanks for all your help

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