# [SOLVED] HP DV9000 Laptop Black Screen works with External Monitor



## iGeekTech (Aug 8, 2011)

Ok so I've done a bunch of diagnostics. You turn on the laptop, you see nothing on the screen, absolutely blank and black. 

You plug in an external, it pops up on the monitor perfectly. Now, the question is, is the INVERTER bad? Or is the LCD Screen itself bad?

The screen isn't dim or anything, nothing shows, I'm just confused whether if it could just be the $40 Inverter or the $100 LCD Screen...


----------



## makinu1der2 (Jan 1, 2008)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Check the connection first. Check that the graphics cable is securely attached.

*dv9000 Service Manual*

If you have a good multimeter you may be able to test to see if the inverter is getting power.

Laptop Repair Help » How to test LCD screen inverter in a laptop

If your not comfortable then maybe have a local shop test it for you.

Search around you should find an inverter for less than $40 (new)


----------



## Dngrsone (Jan 1, 2008)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

If it's just the inverter, then you should be able to reflect a light into the screen and see that the display is actually showing something and there is just no backlight.

If not, then a loose/bad cable as already suggested, or a bad panel.


----------



## iGeekTech (Aug 8, 2011)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Ok so I should be checking...

1. Internal Cables that run from the motherboard to the screen?
2. Inverter, I don't have a multimeter, and I also DO NOT see any display when reflecting light into the screen, therefore, its not the inverter?

So is it most likely either the LCD Screen itself or Cabling?


----------



## Dngrsone (Jan 1, 2008)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Yes. Cabling is cheaper, so I'd try that first.


----------



## Technoob164 (Jun 30, 2011)

This is a common problem with these laptops. They are also difficult to open and manipulate with the display. Good luck.


----------



## GZ (Jan 31, 2010)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*



iGeekTech said:


> Ok so I should be checking...
> 
> 1. Internal Cables that run from the motherboard to the screen?
> 2. Inverter, I don't have a multimeter, and I also DO NOT see any display when reflecting light into the screen, therefore, its not the inverter?
> ...


As my temmate stated, check the cables first. 

The MB connector is located directly above the keyboard, on the left side of the computer. The display connector is located at the top of the display panel. You will need to remove the display and split the bezel to access it.

The service manual that was linked in post #2 will help you through the disassembly and reassembly process.


----------



## iGeekTech (Aug 8, 2011)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Ok, so I checked the cables. The thin one that goes behind the LCD Screen, and the one that plugs into the MB On the top left side of the keyboard as gavinzach said.

I unplugged em, plugged em back in. Still no luck.

I even tried using a DV2000 Screen, the plugs fit, and I even plugged in the inverter....yet nothing appeared on the 13" DV2000 screen. Compared to the 17".

So, now I'm confused what the case may be....

OR is plugging a DV2000 Screen into a DV9000 laptop was NOT going to work anyways?....


----------



## GZ (Jan 31, 2010)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Try connecting the 17" screen to the DV2000. At least you can then verify if the issue with the LCD panel.


----------



## iGeekTech (Aug 8, 2011)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Ok, so I did that, I connected the 17" screen to DV2000. And guess what? IT WORKED! Now I'm confused as hell on what is wrong with the DV9000.

It's not the inverter I suppose, not he LCD Screen, I checked the Cabling....whats next?


----------



## GZ (Jan 31, 2010)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Quick recap...

The computer works on an external display... GPU is okay.
The LCD panel is verified working on another system... Display okay.
When connected to the original computer screen is black...

The most likely issue here is a bad inverter that is failing to light the backlight. A faulty cable can cause the issue, but it is very rare.

I would like you to try the torch test again with a twist... The problem is that the screen contains a few layers of polarizing film and diffusers. This makes it so very little light from outside can get in through the screen... 

To make the image easier to see, I would suggest putting a high contrast image as your desktop wallpaper.

You may need a little help with this... 

Shine a powerful flashlight into the back of the LCD panel. This should cause the screen to light dimly since you are shining the light through the diffuser. Look carefully and see if there is an image on the LCD panel.


----------



## iGeekTech (Aug 8, 2011)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Ok, and by putting a high contrast image as the wallpaper, I'd have to connect it to an external monitor, set the wallpaper, disconnect the External Monitor, and flash the light to the back of the LCD Screen? Or front of it where it's black?


----------



## GZ (Jan 31, 2010)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Shine the flashlight on the back. The plastic backing of the display is much more receptive to light than the front.


----------



## iGeekTech (Aug 8, 2011)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Ok so I just tried using an Inverter from a DV6000 Laptop and plugged it in to the DV9000 Laptop, and still nothing....the Inverter works too, when I plug the 17" screen to the DV6000 it worked with the same Inverter....

This is really frustrating...-__-


----------



## iGeekTech (Aug 8, 2011)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

FIGURED IT OUT!

It was the cabling. Surprisingly. I obtained the good cable from the DV6000 Laptop and added it to the DV9000 (Great thing they were so compatible) and WALA! It worked, so I'm going to have to order the cable somewhere online.

Anyone knows what this cable may be called? Its the one from the MOBO, to inverter, and to the LCD Screen. 

Inverter is fine, LCD Screen and Panel is fine, the cabling is somehow bad. Who knows HOW! But its bad.


----------



## GZ (Jan 31, 2010)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*

Glad we were able to help you get it sorted!


----------



## iGeekTech (Aug 8, 2011)

Thank's gavinzach :] Really appreciate it!


----------



## Dngrsone (Jan 1, 2008)

*Re: HP DV9000 Laptop Black Screen works with External Monitor*



iGeekTech said:


> FIGURED IT OUT!
> 
> It was the cabling. Surprisingly. I obtained the good cable from the DV6000 Laptop and added it to the DV9000 (Great thing they were so compatible) and WALA! It worked, so I'm going to have to order the cable somewhere online.
> 
> ...


It's bad because it is moved around every time the lid is opened and closed. Of course, it is designed for that, but they do wear out.


----------

