The Inverter is what goes out 90 percent of the time.
An LCD screen cannot produce enough light by itself. It needs an additional light source.
A Backlight is used to provide the additional light source.
A Backlight is a CCFL. Cold Cathode Fluorescent Lamp.
Similar to Fluorescent bulbs, (lamps), use in homes, and businesses, but on a Much smaller scale.
An Inverter is used to provide power for the LCD screen, and the Backlight.
A laptop's power source cannot provide enough power for an LCD screen.
The Inverter does.
A laptop's power source provides too much power for a Backlight.
The Inverter reduces the power.
An Inverter slowly goes bad as a general rule.
A Backlight goes out all at once.
An Inverter is a small circuit board located in the Display Assembly.
The Display Assembly generally consists of the top cover of the laptop, the LCD screen, (assembly), the Backlight, Metal frame going around the LCD screen assembly, the Inverter, Wireless Antenna, Bezel, and various fastening screws.
(The LCD screen is an assembly. It consists of layers, held together by the above mentioned metal frame)
The Bezel is the thin plastic frame that surrounds the LCD screen, in the front.
Once the Bezel is removed, you will have access to the Inverter.
As I am sure you are aware, HP bought out Compaq.
HP Support > Compaq Presario CQ50-110us Notebook PC > Manuals,http://h10025.www1.hp.com/ewfrf/wc/manualCategory?lc=en&dlc=en&cc=us&lang=en&product=3752689&
On this page I would like you to scroll down, and click on the Service Manual > (Free, and in PDF file form),
HP G50 Notebook PC and Compaq Presario CQ50 Notebook PC - Maintenance and Service Guide.
This is a PDF file. After you click on the above file name you won't see anything happening right away.
The file is downloading in the background.
(I downloaded this file just now. Took 4 seconds to see the first page, and an additional 41 seconds to fully download. Watch the Download Progress Bar, and let the file download all the way before looking through it)
In the Bookmarks menu to the left, click on the + sign next to > Removal and replacement procedures
Now click on the + sign next to > Component replacement procedures
Finally scroll the file tree down a little bit, and click right on > Display assembly
[ You may wish to reduce the view size to 125% or 100%. Go to the top header, and click on the Zoom Out icon. ( - ) ]
Page 61 in the PDF page number box shows you where the Inverter is located.
(Top header to the right of the blue down arrow)
BEFORE you start:
1) Work on a table
2) Remove ALL power to the laptop. Remove the AC adapter (Charger) and Battery
3) It would be advisable to buy, and wear an ESD wrist strap. (Electro Static Discharge)
Connect the alligator clip to a good ground source.
(I connect to the metal frame of an empty desktop computer case, for example. You may have an object that is similar)
The cost of an ESD wrist strap averages around $3 to $6. An economical $3 ESD wrist strap will do just fine for this one-time procedure.
[ Your body carries Static electricity. Static will fry out (Short Circuit) the hardware components inside a computer. An ESD wrist strap connected to a good ground will keep your computer safe ]
4) Use a multi-compartment container for the various screws you will remove. label the individual compartments for the area the screws came out of. Some of the screws look VERY similar to other screws. You Don't want to mix them up.
[ You can use a clean egg carton in a pinch. Label each egg holder ]
5) After all power is removed you have to remove in order;
A) The WLAN Module. Page 49
B) The Keyboard. Page 52
C) The keyboard Cover. Page 54
D) Then the Display Assembly
From a quick search, for an Inverter for the Compaq Presario CQ50-110us Notebook PC,http://www.nylaptopparts.com/index.php?main_page=product_info&products_id=883
For additional questions please post in a Comment.