【 Weak current College 】 LCD display text or images very bleak

Notebook as you work, the LCD itself is not illuminated, it needs to be achieved through the backlight lamp, the lamp light lighting issued through the LCD screen after transmission, we can see clearly the LCD display. From the principle that the notebook motherboard for low-voltage DC first go to boost circuit board, circuit through switching to high frequency high voltage power, then the LCD backlight lamp is lit.
If, after powering on the notebook, LCD display text or images very bleak for backlight lamp does not work, this happens because there are two: one is to drive the backlight lamp of booster circuit damage; second, the lamp itself is damaged.

While the LCD is whole notebooks in the most precise, technical content in the highest part, but once mastered it works, bold, observant, can do it yourself this kind of failure. Of course, in practice, to have the following tools: electric iron, high-quality solder wire, Rosin, Blade, digital multimeter, screwdriver, etc.

First step: open the enclosure of the LCD. We put decorative lid open and place the bottom screw unscrew to disassemble LCD shell (some notebook LCD of screws on the sides). The notebook shell generally use buckle design, unscrew the screws, you want to use a small screwdriver to pry off the gaps, and slightly along the horizontal stroke forced open Office, you can open the buckle.

Note: in the prized buckle, screwdriver, not too deep into the inside of the machine to avoid damage to the internal components, while at the same time, when the prized clip can not be too hard, otherwise it will cause the shell deformation or damage to the card.

Step 2: open the shell, you can see the notebook LCD's internal structure, from notebook motherboard leads a group of wire, the wire's main role is to provide the Board and the current control signals into boost plate, and the function of Pressor Board is the Board's 12V direct current is converted to a backlight lamp work of high frequency voltage necessary, while at the same time by the Board of control signal to open or close the LCD lamp, adjust the brightness of the lamp. The high-voltage power after step-up is conveying gives the lamp on the LCD, and driving lamps.
Step 3: determine whether a wire damage caused by the fault. Multimeter measuring input voltage step-up plate is working properly, or the whole notebook apart, multimeter measuring cable ends are circuit breakers. If the discovery is traversing circuit breakers, cables cut in two and wiring, to solve the problem.

Note: some notebook is a soft printed foil cable, copper foil once more trouble breaking it, the best way is to replace the copper wire, if not possible, you can look through printing foil, locate circuit breaker points and wallpaper scraping knife copper foil surface, welding with electric iron, you can quickly solve the problem.

Step 4: If the cable is no problem, we can boost plate for testing. Testing boost plate the simplest way is to test the step-up voltage output Board. However, due to the boost plate output voltage up to several thousand volts, test accidentally caused by shock or damage boost plate. Therefore, for a certain electronics knowledge and equipment for lovers, recommend using a multimeter or oscillographic system detects the beginning of the oscillations are for oscillation caused by bad judgment boost plate.

While there is no test condition of enthusiasts, we can use induction pencil directly in boost plate oscillation transformer or output cord attachment tests for induction voltage (in test, simply open the laptop power supply, without pulling out output plugs and oscillations on the cover) to determine whether the normal working pressure plate. However, because some of the notebooks of electromagnetic leaks is large, this way possible misinterpretation of the phenomenon. To avoid this situation, we can first will boost Board input wire removal, open notebook, pencil test booster used induction plates are there electricity, if you have electric pencil displays, portable electromagnetism is large, do not fit this way test.

Step 5: If you determine that the wire and boost Board there is a problem with a basic can be concluded that the failure of the lamp. We can be shown in Figure 2, unscrew the fixing screw for liquid crystal panel, LCD Panel from the chassis.

Note: 1. removal prior to the LCD display signal cable and lamp voltage unplug from the socket to avoid removal of the pull wire's fault and the damage. 2. because of the low intensity of LCD panels, easily damaged and under the action of external forces is expensive, so we in the demolition process, care must be taken to protect the LCD screen, avoiding the LCD fall or be sharp scratches and damage.

In the LCD screen removal has been completed, still do not see the light. At this point, you need to enclose the liquid crystal screen shield screws down on. Tighten the screws, in order to protect the LCD Panel and the rear of the drive circuit, it is recommended that you place a piece of foam on the desktop, and the LCD Panel of the down twisting tube fixation screws. Unscrew the screws can be decomposing the LCD Panel. In the decomposition of the backlight and LCD Panel, drive circuit and fixed support, be sure to carefully, paying particular attention to the protection of the signal line, avoid the pull and the signal cable is damaged.

Step 6: in the finished this work, you can see the true face of the tubes, from appearance, the backlight lamp extremely thin, only core thickness as a ballpoint pen. We can take the offending lamp to the market to buy the same types of products, in General, the market value of the tubes is about 50-100 rooms.

Note: the length of the tubes and the original lamps agreed to, and take the lamp must be careful to avoid the lamp broke during transport.

Lamp buy back, we may, in accordance with the demolition of the reverse order when you reinstall the lamp. But be careful when installing, especially the lamps installed protection cover, forced to balance, otherwise easily lead to rupture of the tube.

Special reminder

All installationFinished, you can try machine, here need to remind you that in the trial when it is best to remove the laptop battery, power supply adapter on the machine, so that, once found irregularity can be quickly disconnected from power, to avoid failure.