Black screen on L17lcd2

Sounds like the backlight has failed.

It sounds like your backlight is out or barely functioning. Try replacing the inverter board(s). Since you can see a picture, the T-Con board is probably okay.

You might have either a faulty LCD cable or screen inverter board.
The LCD cable transfers data signal from the motherboard & video card to the LCD screen. It also supplies high voltage DC power to the screen inverter board. The screen inverter board works as a power supply for the backlight lamp mounted inside the LCD screen. It converts low voltage DC power to high voltage AC power needed for the backlight lamp.

In this service manual, you will find an illustration of how to disassemble the laptop & replace either the LCD cable or screen inverter board:
http://h10032.www1.hp.com/ctg/Manual/c01295820.pdf

The culprit will be the inverter board of your LCD screen that drives the backlight, my nc8000 shows the same symptoms after 6 years of heavy daily usage. After pressing the LID sensing button near the right hinge the backlight usually remains on, but sometimes you have to press it several times under a minute once it finally stays on. The proper fix would be to disassemble the screen and replace the inverter board, as the LCD and the CCFL backlight tubes are perfectly fine in my case.

On how to remove the screen from the laptop, you can get help from this HP guide:
http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c00803690/c00803690.pdf
(it's in section 5-35, that starts on page 128)

Unfortunately, I can't help you out on the other part, on how to disassemble the screen itself (but I suspect it has 4 or 6 screws under the rubber "feets" on its front), and I can't help you out in fixing the inverter board itself either...
If you want to fix the board yourself, you have to be able to wield the soldering iron perfectly, and your goal will be to replace some capacitors (they are usually bulging, so you can identify them being the culprit by the naked eye too).
The other option is to order a replacement inverter board, and simply swap the bad with the new one, it is still more economical than to buy a new display assembly as a whole; some chinese manufacturers are available, but I bet you can find some source more closely to your current location, just google for:
hp nc8000 inverter board

Ur LCD inverter backlight board is dead.Replaced this LCD inverter backlight board will get ur picture back.Tries websites Shopjimmy.com,Ebay.com to buy a refurbish LCD inverter backlight board for the replacement.It a long board in shape.

Ur LCD inverter backlight board have problems,just not dead yet.When ur LCD inverter backlight board is dead.U will get only sound and no picture at all.

ruth_coleman, Only a guess but I would say that the "switch-mode-power-supply" or "backlight inverter power supply" has a problem. Is screen always BLACK? how old is unit? How many "ON" hours on this unit? Is unit new? Out of warranty? Did it ever display a PERFECT IMAGE on it? When? Did it always HUMM?? FYI check out VIDEO clips of LCD monitor disassembly and repair on YOUTUBE to find out what is inside a typical LCD display. You will have a better handle on what to do about getting it repaired or to trade in for new. Yes, monitors can be REFURBISHED with new SMPS/Inverter boards for $50-$100. Check out some ADs here on fixya. I'm louie12fix on fixya or [email protected] please rate this response and get back to me if you need further assistance. Bye for now.

You need a new screen or inverter, depending on the problem. You can't replace the backlight itself because it is build into the LCD panel. Using a mercury reaction, it makes light. Because of the mercury, it is also dangerous to replace.

Sounds like your backlight or inverter is on its way out. You can pick one up on ebay.  Google how to check backlight/inverter issues with your model.

No it is not a backlight it is the inverter board which sends power to the backlight most likely cause is bad capacitors on the inverter board. this wil require soldering to repair backlight is even worse it requires you to disassemble the lcd unit. if you are gong to ope up the lcd monitor look on all pcb boards for deformed (blown) capacitors replace those with identical ones from yur electronics shop9they must be exactly the same mfd (Microfaradays) and Voltages