Why dell latitude d810 laptop screen black works on external monitor?

SOURCE: lcd screen black on laptop. External monitor works.

Defective CCFL backlight may has the following symptom:

• Screen flashs on red/pink and off.
• Picture stays on in red and slowly be come normal.
• Picture flickering with dim display.
• Picture flickering on and off.

All these symptoms indicate that the LCD backlight lamp (CCFL Lamp)
has reached the end of the life and all you need to do is replacing the CCFL lamp

Connect an external monitor to your laptop and power it up, if you see the normal Windows images then the video card and laptop is OK and the problem is definitely the backlight.

Dim image and/or dark display on the laptop's LCD screen indicates a faulty LCD backlight and it could be the inverter that supplies high voltage to the CCFL lamp or it is the CCLF lamp is nearly burnt out or burnt out, most likely this is the case.
The inverter can be replaced easily but the CCLF lamp is more time consuming and requires soldering skills.
Check out www.lcdparts.net for parts, repair service and DIY info.

SOURCE: I Can't turn on my Dell Latitude D810 Laptop

From your description, it sounds like a motherboard failure. Generally about $100 on Ebay.

SOURCE: very dark display screen almost black,dell latitude d810

Hi

Thank you for your query

Please try the following key combination

fn + Up Arrow
fn + Right arrow

If the above fail then it will be the inverter of the screen which will need to be replaced, please book the laptop into a reputable PC shop for replair

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SOURCE: dell latitude D610. Screen goes black. External Monitor OK.

Make sure you have not accidentally used the FN+F5 key
That combination sets the laptop to use an external display.

If using that does not give you a display take a small torch (flashlight if in USA) and shine it at an angle on the laptop screen.
If you can see any sort of picture you would be looking at replacement of some minor parts to the laptop screen

Hope this gives you the information you need. If not add any extra information you may have and lets see if we can FixYa

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