Screren has power but black display

Hi,
My point of view RAM section direct connect to display so first you check RAM.Then check processor Fan proper working or not. and finally power connection in screen.
Thanks..

Failing Inverter An inverter, typically found inside a laptop computer, consists of a small board, which has impregnated electronic circuits stamped on it. Inverters look like thin boards about the of two sticks of chewing gum. The inverter and its bulb control the intensity of the liquid crystal display, which lights the screen monitor. The computer can control the output voltage of the inverter and either lighten or darken the screen. A special type of inverter can adjust the brightness of the screen by using an internal sensor to judge the room brightness, and then adjust the screen accordingly. Failing inverters give off some specific warning signs, which can be recognized by observing different screen characteristics.

Short Intermittent Display Upon turning on the laptop, the screen flashes on in the normal mode for a short period and then blinks to black. A very faint image appears in a dark background, which will be very hard to see almost invisible. After shutting off the laptop and restarting, the same mode occurs, where the screen appears normal for a few seconds then fades to black. This condition points to a failed inverter. To confirm this, plug in an operational external monitor; if the external monitor functions, the inverter has failed. b> Total Blackout with Ghost image b> The laptop turns on, as indicated by the power supply button, but the screen comes up black. The screen comes up black after restart. You might be able to detect a very dim or ghost-like image on the monitor. When you plug in a known functioning external monitor, the external monitor operates normally. This mode of display indicates a failed inverter. b> Long Term Periodic Operation b> With this failure mode, the laptop screen illuminates normally upon start-up and remains that way after several minutes, hours or even days, until it goes very dark again. Brightness controls or restoration attempts do not work. Most often, the screen will function normally with a computer restart, but will eventually return to black. Faint ghost images might appear, as seen in the total blackout mode. b> Dark With Color Variation b> Upon computer start-up, the monitor shows black or dark gray, accompanied by very faint images. The screen might have an intermittent color change, or remain on with a non-standard color variation, like pink or red. b> Auto Control Switch b> If the screen appears black, with no faint or ghost images, look for the lid switch near the back hinge. The switch, when depressed with a closed lid, shuts off the computer and monitor functions. Sometimes the switch becomes stuck in the closed position, disallowing the computer and monitor to turn on when opened. Pushing the switch manually several times can often free it up. If the switch tab has broken or jammed inside the case, it needs replacing. b> Loose Connection In this mode, the display looks normal upon start-up, but tapping the side case of the computer turns the screen black. More tapping results in the screen functioning normally then cutting out again. This condition points to a loose wire connection from the inverter to the LCD backlight lamp, or the video cable. The connectors can be accessed by removing the monitor bezel screws and pulling the plastic retainer off. Both connectors can be cleaned and refitted.

I had a similar problem. Hold the menu button for 5 seconds to unlock it.

Well, I don't know what your model number is or how old your computer is, but I also have a Compaq Presario Notebook and there is currently a lawsuit going on something about the graphics/video cards in some laptops/notebooks being defective. You would have to go on their website and check the list of computers to see if yours is involved or not. I know that visual and video problems were happening as well as network adapter problems.
Here is the site:

http://www.nvidiasettlement.com/

The backlight invertor seems to be defective.
Check the main power supply board for bad capacitors (visible damage ) and make sure that the invertor tubes do not light up for a moment when you power up the monitor ( in that case their probably is one or more light tube defective (burnt)) --

Try using an external monitor. If it works with this, the display board may be out. If you can see the faint image shining a flashlight diagonally at the screen, the backlight is burned out. It should be practical to replace the display if it's still a good computer otherwise.

Press and hold the Power button for 45 seconds to turn the laptop off.

Then, remove the battery from the battery compartment and clean the metal contacts.
Next, reinsert the Battery and try to turn it ON.

If the display still doesn't come then you may try connecting an external display to check if the Computer is able to produce display and the issue is with the backlight of the LCD screen.


wish u good luck!!!!!!!!!!!

Boot to Safe-Mode by pressing the "F8" key several times when you first see the windows logo screen. Answer "yes" to enter safe mode. "Right click" on "My Computer", select "Manage", then "Device Manager". Expand "Display Adapter" by clicking on the "+ sign" on the left side of Display Adapters. Highlight the Adapter listed under the Display Adapter line by "left clicking" on it. Then press the "right mouse button" and select "uninstall" to uninstall the display adapter. Now reboot you system (not safe mode) and see if it works. The display text may be very large now. If it works, you need to find your drivers cd that came with the computer and install the video driver using the above procedure but selecting "update driver" instead of "uninstall"

Sounds like the backlight for the LCD is dead, either the light itself or the power inverter. If you're not a tech, you should take it in for repair. If you are a tech, you can usually find replacement lamps and inverters on EBay. Hope this helps.

-kinerf