SOURCE: My HP pavilion g7 laptop's screen is gone dark,
Primer first, jhb4954;
An LCD screen cannot produce light. It needs an additional light source.
http://solutions.3m.com/wps/portal/3M/en_US/Vikuiti1/BrandProducts/secondary/optics101/
A Backlight is the additional light source.
A Backlight can be a CCFL or a series of LED lights.
A CCFL is a Cold Cathode Fluorescent Lamp.
Similar to Fluorescent lighting used in homes, and businesses, but on a MUCH smaller scale.
(Average size of a CCFL is 2mm Thick, and Length is almost as long as the LCD screen is high. { 2mm is a little more than 1/16th of an Inch.
.0625 = 1/16th of an Inch. .0787 = 2mm )
A screen Inverter is used to convert the power (Electricity) from the laptop, for the LCD screen, and Backlight.
A small circuit board approximately 3/8ths of an Inch in Height, and 3 Inches in Length. (Varies as to screen Inverter model )
Located behind the Display Panel Bezel, and mounted at the bottom of the LCD screen.
Usually mounted with one Philips head screw, and has two cables going to it.
Video Cable, and cable to the Backlight.
(Plastic thin frame in front of LCD screen, and resembles a picture frame, is the Display Panel Bezel. HP's name.
The LCD screen is the Display Panel )
Primer over.
The HP Pavilion G7's series came out with EITHER using
CCFL, OR LED lights for backlighting.
Just depends on what model number it is.
[ HP = Manufacturer
Pavilion = Model Line
G7 = Model Series
In the white Service Tag located on the bottom of the laptop, is P/N.
This = Product Number
HP's model number ]
1) NOT all LED backlit LCD screens use a screen Inverter.
2) a screen Inverter is the problem 90 PERCENT OF THE TIME.
Which leads us to several options;
Option 1:
Your Pavilion G7 LCD screen uses a CCFL for backlighting.
It also uses an Inverter. (screen Inverter)
90 PERCENT OF THE TIME the fault can be attributed to a bad screen Inverter.
A relatively inexpensive part. It is also MUCH more easily accessed, than trying to replace the Backlight. (And much cheaper than replacing the LCD screen)
Test a screen Inverter? Requires a sensitive multimeter. Read - fairly expensive,
http://www.fonerbooks.com/test.htm
Because of the low cost, ease of accessing to replace, and lack of proper test equipment, most users at the consumer level just replace the screen Inverter.
A parts changer type of repair granted, but when viewing the alternatives this may be the only viable solution.
[ Note*
An LCD screen and a screen Inverter are a MATCHED UNIT.
When replacing the screen Inverter make SURE you get the proper one]
Screen Inverter replacement doesn't repair the problem?
Then the decision is made whether to attempt replacing;
A) The CCFL, (Or CCFL's { 2 }, if the model uses it ),
Or,
B) Replacing the LCD screen as a unit.
The CCFL is a Fluorescent bulb. Means it has Mercury inside.
It is also VERY thin in Width. Means it can be broken easily.
It is also more difficult to access;
Primer:
An LCD screen is composed of layers. This can be seen in the first link I posted.
These layers are kept together in a specific pattern, by the Screen Frame. (Left to Right, Top to Bottom, as well as the layer's order )
A thin metal frame which surrounds the LCD layers.
[ Two styles of Screen Frame used, to my knowledge;
1) Two piece. One Top part, and one Bottom part. Resembles two picture frames put together, but they each have a lip like a cake pan.
One slips inside the other.
Small countersunk head screws hold the two parts together.
2) Four piece.
Top, Bottom, and two Side pieces. Uses countersunk head screws also)
The CCFL is usually on one side, and right under one of the Screen Frame frame rails, (Unless a dual CCFL model. One on each side ),
http://www.laptoprepair101.com/laptop/2007/12/09/replace-laptop-backlight-ccfl-lamp/
{ Note* Sometimes a CCFL is not offered separately from the LCD screen, by looking up it up with the laptop model number. In this case a match is made, by using any identifying manufacturer product codes on the bulb ]
Option 2:
Your Pavilion G7 uses an LCD screen with LED backlighting,
AND it uses a screen Inverter.
Suggest replace the Inverter first.
Then if this does not fix the problem, replace the expensive LCD screen.
Option 3:
Your Pavilion G7 uses an LCD screen with LED backlighting. Does Not use a screen Inverter.
Replace the LCD screen is the only option.
Several HP Pavilion G7 LCD screen models. Some with CCFL, some with LED,
http://www.screenaid.com/hp-laptop-lcd-screens-pavilion-dv7-series-c-1204_16810.html
This is HP Support > HP Pavilion G7-1075DX Notebook PC > Manuals download page,
http://h10025.www1.hp.com/ewfrf/wc/manualCategory?cc=us&dlc=en&lang=en&lc=en&product=5093430&
Left-click on the first file listed, for a free Service Manual, for the
HP Pavilion G7 series of Notebook PC's.
(I just picked a model number to access the Service Manual, for the entire model series. Just from my experience )
This is a PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.
After you click on the file name it may take up to 30 seconds, before the first page comes up.
(Took 10 seconds using medium speed DSL connection, just now)
If you wish post the Product Number in a Comment, and I will guide you in replacing.
Regards,
joecoolvette
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