Why there is noise when adjusting the screen brightness?

As the screen brightness adjusting is achieved by changing the screen size of the coil current. It is a normal physical phenomena the coil current changes in electricity eventually lead to the coil make voice. Because of the sensitivity of the human ear and different coil quality and shielding technology, the final results differ in the sound performance.  

Why the screen around would heat?

Actually, the location of heating is the ignition coil in the LCD screen.That is the normal thing the location of the ignition coil heat after working a period of time.

What causes that a bright spot than elsewhere in screen ?

This phenomenon is known as LCD bright spots, is a physical injury of liquid crystal screen . I t is mainly due to the screen panel by the external pressure or got the heatand lead to a slight deformation.

Will the defective pixel on the LCD screen spread?
Certainly not. Each point of a liquid crystal particles on LCD screen are relatively independent, non-influence each other.

Why you can see displayed vaguely while the screen in not bright?

This situation is due to backlight or ignition coil which control the screen backlight damaged.

What’s the difference between bright spot and dark spot?

In fact, they are all belong to defective pixels whether it is bright or dark spots. The black spots are relatively less vulnerable to note that become dark spots. If it is red, green, blue or white spots,  they are easy to be noted because the color is lighter in the backlight, so it is regarded as bright spot of habit.

Can defective pixels be repaired?

Possibly not. LCD screens defective pixels belonging to the physical damage, and therefore can not be repaired.

How do I clean the stains on the LCD?

You can buy the LCD screen special cleaning agents.Remember not to use corrosive organic solvents (such as alcohol, etc.) and water to wipe out LCD screen. When you are wiping, please shut down first and pay attention to according to a certain direction, suggested that volume growth in a soft cloth strips, and then from left to right or from right to left, one-way cleaning, finally let the screen dry naturally.

How defective pixels happen?

LCD screens defective pixels is a physical injury which can not be avoid in the production and use.In most cases it is produced on the screen manufacture, it also can result in defective pixels in use by the impact or natural wear and tear. Defective pixels will be generated as long as a single pixel or more which are composition of the three primary colors, while the production and use are likely to cause damage.

What are defective pixels?

The pixel phenomenon, more common than “missing/dead” pixels, results when a transistor occasionally shorts on and results in a permanently “turned-on” (red, green or blue) sub-pixel.There are some possible corrective measures, such as “killing” a transistor using a laser, however, this just creates black dots which would appear on a white background. Fixing the transistor itself is not possible after assembly. Additionally, it is not possible to turn a “lit” pixel off, except for the aforementioned laser method, which essentially just makes the transistor inoperative, thus resulting in a black dot.

What does TFT mean? What is the difference between TFT and LCD?

LCD (Liquid Crystal Display), is the LCD screen. Are generally divided into two kinds of monochrome and color LCD screen, monochrome LCD is currently almost out of the notebook market, while the color LCD is still sustainable development. STN color LCD and TFT mainly divided into two kinds, of which TFT (Thin Film Transistor) LCD, also known as active-type electric crystal thin-film transistor liquid crystal display, which is known by many people’s true color LCD display; DSTN (Dual -Scn Twisted Nematic) LCD, dual-scan LCD screen that is. Is an STN LCD display is now out of the market.

What is the meanning of VGA, SVGA, XGA, SXGA +, SXGA, UXGA, WXGA, WSXGA ?

The letter combinations represent different LCD specifications, including VGA for the 640 × 480, SVGA is 800 × 600, XGA is 1024 × 768, SXGA is 1280 × 1024, SXGA + is 1400 × 1050, UXGA for the 1600 × 1200, WXGA for 1366×768,WSXGA for 1280×854.

How to restore the dark screen to bright?

Lamps have already gone out if you confirm that the screen is brightest and still evident dark than before when used in AC power supply. You must replace the corresponding models of lamp.

Will the heat affect the LCD?

Only the heat reach a certain temprature. For example,  it will lead LCD screen appear a row of dead pixels or make LCD brightness uneveen of you put screen direct expourse under the sun. But it does not have any effect when work in the generally heat .

What are laptop screen size ?

Generally are 10.4-inch, 12.1 inches, 13.3 inches, 14.1-inch, 15-inch, 15.4-inch, 17-inch. At the same time the majority of notebook screens are now using a widescreen LCD. The same diagonal size LCD, the actual size of wide-screen is smaller than the normal 4:3
screen.

Does laptop screen have radiation on the human body?

Any electronic device will have radiation on the human body, but the laptop’s LCD screen is much smaller as compared with CRT display inthe radiation on the human body. Laptop screen can be very easy to reach environmental standards, is a relatively green
electronic products.

How to open LCD screen reduce shaft wear and tear?

The best way is using both hands to open and close the screen softly and slowly, and avoid uneven dictate your hands on the screen, that can delay the screen deformation and fracture which due to uneven force.

Can replace the screen backlight tubes?

Sure. However, you must use the corresponding types of backlight lamp. To replace lamps also need to disassemble the screen. It may damage the the reflector panels and TFT panel, eventually leading LCD screen display not as effectively as before. We do not recommend this method unless can not find can be used screen. If you must adopt this approach, please entrust professional maintenance staff.

Is it able to link laptop LCD screen to desktop computer?

The answer is yes, but it is a difficult problem. If you want to implement this idea, you must transform the laptop LCD screen lamp, liquid crystal display power supply, data cable, frame fixed and other parts, so that it can compatible with desktop graphics cards. It is really difficult.

Some would-be home laptop repair techs give up because they can’t get the rubber pads out. In some instances, as with this Dell, you really need to dig something fairly sharp and stiff into the cavity to get under the plug. I used a jewelers screwdriver in this case. Once you remove the rubber bumpers, you’ll expose a regular Philips head screw. Some laptop manufacturers put a little glue on there to keep the screw from loosening, in this case Dell didn’t, they probably figured it’s hard enough just to get the rubber out. Don’t rush into tearing the screen apart without troubleshooting the video problem first.

Once the screws securing the plastic bezel are removed, you still have to unsnap it from the body of the lid. If you’ve never worked on the particular notebook model before, you don’t know where the plastic latching tabs are, so it’s a bit nerve wracking. You can see the main locking tab holding the screen bezel on this Dell Latitude about halfway down the side of the bezel. The circuitry to the right of the LCD is the inverter that provides the high voltage for the backlight.

Sometimes you can locate hidden tabs with a thin screwdriver, sometimes I just keep a steady force on the bezel and pry. When you locate the sticking point, if should release if you push in on the bezel at that point to free it from the notebook lid. Here I’m lifting the whole bezel off our Dell laptop, exposing the inverter circuit to the right (you can also see it above), which is a standard placement. The only function the bezel serves is as a cover, removing the screws doesn’t free up any of the components.

The LCD screen is secured to the back of the Dell laptop lid with four screws. The light grey metal structure you can see on the front isn’t actually part of the LCD screen, we’ll be removing it later. It houses the backlight and the reflector, keeping the whole assembly together as one unit. This Latitude LCD assembly is a much more modular design than the Toshiba we disassembled in the last page.

Once the screws are removed, I stood the LCD assembly on the keyboard while removing the connectors. The first connector I removed was the simple ribbon cable which delivers the digital video signals (addressing for the LCD matrix) to the Latitude screen. It’s a simple push together connector that I removed by grasping it right at the connector and gently pulling it out.

Here I’m removing the inverter connector. The inverter circuit powers the backlight in our Dell, a CCFL (Cold Cathode Fluorescent Lamp), which requires a high voltage to strike a plasma. CCFL tubes actually have better life expectancy than the inverters, so most techs will try replacing the inverter before fooling around with removing the backlight. I illustrate removing the inverter board from a Toshiba Satellite here. You can find replacements on the aftermarket fairly easily for most models.

Now we get to removing the grey metal structure that secures the actual LCD screen to the backlight assembly. The design used a dozen little metal tabs that are bent into depressions in the white plastic holder, and which are easily opened with a small screwdriver. Dell also saw fit to tape the units together on the top and bottom. I just undid the tape on the top and left it on the bottom as a hinge.The LCD screen from this Dell Latitude utilizes a nice translucent light panel, in addition to the backlight, The purpose of the light panel is to spread the light from the backlight equally behind the LCD for even backlighting.

The CCFL backlight itself is secured over the top of the LCD screen in a channel with a thin strip of copper tape. The tape is reusable, at least it held up through this extraction and replacement. Dell really seems to have a tape thing going on with this Latitude:-) Once the CCFL backlight is exposed, you can pull back the little rubber insulators on the ends and unsolder it. Yup, the tube is actually touch soldered to the inverter leads on either end. Below I show the exposed backlight on a black background. Assembly is simply the opposite of disassembly.

Source from fonerbooks.com.

Most Toshiba laptops use four screws to secure the plastic bezel, two at the top and two on the hinges.The top screws are hidden under some rubber bumpers, you really need to dig a screwdriver with an edge on it into the side to compress them enough to get them out. The screws below the LCD on the hinges are under rectangular paste ins that I needed a jewelers screwdriver to pry up.

In all cases, the screws securing the plastic bezel around the laptop screen had some variety of loc-tite on the threads, and need a good deal of force to remove. It’s critical to pick a screwdriver that matches well so you don’t end up stripping the head.

Once the screws are removed, we gain access to the LCD with it’s backlight and inverter by prying open the plastic shell. It takes a sharp screwdriver to get it started unless you know exactly where to push in the snap-together injection molding. The funny thing about notebook computers is that they are actually incredibly tough, I’ve never broken one while working on it, even when I didn’t have a clue how it was put together. Once you pop a couple of the snaps, you can sight down the crack and see where the others are, which makes it a lot easier.

I don’t have any particular order for doing this, so I started with removing the backlight from the top of the LCD. The backlight is secured to the LCD by two small screws that do require a jewelers Phillips to remove. Laptop LCD backlights are actually florescent bulbs, with CCFL (Cold Cathode Fluorescent Lamp) being a favored technology. The average life for a laptop backlight is on the order of 30,000 hours, or more than three years of 24 hour a day use. When the backlight in a laptop flickers or fails, it’s more likely the inverter than the CCFL tube.

Here we have the backlight removed from the top edge of the Toshiba screen (the LCD is actually manufactured by Sharp). It’s a pretty simple design, one wire goes to each end of the tube, just like a regular florescent tube, and the inverter produces the high voltage, high frequency energy required to strike a plasma and keep it lit. This isn’t terribly efficient, and newer laptop computers employ LCDs that don’t require a backlight, which helps a great deal with battery life. The CCFL tube is tacked to the wire at each end with solder since it’s not really intended to be disposable.The inverter that drives the backlight is a much more frequent cause of failure than the CCFL tube. The inverters are sold as modules, frequently remanufactured, for between $60 and $80 for most laptop models that employ them.

It can be very frustrating to get a lemon version of a laptop that goes through inverters, particularly when the warranty expires. Removal and installation of the backlight inverter is actually pretty simple once the shell is open. Two screws hold this Toshiba inverter to the case, and there are also plastic guide pins for aligning it. Two plug in connectors, one for the LCD backlight (below, left) and one for the inverter control (below), complete the installation or removal. The final picture in the series is really just a reminder not to forget the LCD ground when you reinstall the LCD in the shell.

Source from fonerbooks.com.