LCD screen white screen failure analysis and solution

My monitor is Samsung 940BW, used for a year and a half, today when using the computer without any indication of white screen, the screen is pure white, the host is still normal The operation of the ground, I turned off the display and then turn on the display, the data line behind the display is still the same. So what is the problem?

After the LCD screen is turned on, the displayed screen becomes a full white (white screen) fault, which is the fault phenomenon of the white screen of the boot screen. LCD LCD screen boot black screen, blue screen fault is more common, black screen, blue screen are system or hardware problems, and the screen boot white screen fault is generally the LCD LCD screen itself fault, let's take a look at the boot screen The cause of the white screen failure and the maintenance idea.

The cause of the malfunction of the white screen of the boot monitor

The white screen fault of the LCD panel may be the LCD panel driver circuit problem, the LCD panel power supply circuit problem, the screen line contact failure, the motherboard control circuit problem, etc. caused. Since the LCD screen turns on after the white screen, the backlight and the high voltage generating circuit work normally, but the LCD panel does not get the driving signal. If the screen disappears after the laptop is turned off, and then the white screen again, it may be caused by a power board problem.

From the analysis of the fault phenomenon, the LCD screen is powered on or off. As long as the power is plugged in, the high voltage generating circuit is always in working state and the backlight is always lit. That is to say, the high voltage generating circuit is not controlled by the switch, that is, the switching signal sent from the main board to the high voltage generating circuit is out of control. Since the switching signal from the motherboard microprocessor is usually controlled by several transistors, the fault may be the damage of the triode that controls the switching signal.

Troubleshooting the white screen of the boot screen

1. First open the outer casing of the LCD panel, and then check if the screen interface is loose or not connected. Check that the screen cable is connected properly.

2. Then turn on the power switch of the notebook computer, and then use a multimeter to measure whether the power supply voltage of the screen line interface is normal. If the supply voltage is normal, go to step 5; if not, then check if the fuse or fuse in the vicinity of the screen output is open or damaged. If it is damaged, replace the damaged component.

3. If the fuse resistor or fuse inductance near the output of the screen line is normal, then check whether the output voltage of the DC-DC voltage conversion circuit that supplies power to the LCD screen is normal. If the output voltage is not normal, check the fuse resistor, PWM controller, switch tube, inductor coil, filter capacitor and other components in this power circuit, and then replace the damaged components.

4. If the output voltage of the DC-DC voltage conversion circuit is normal, it is a component such as a capacitor between the output of the DC-DC voltage conversion circuit and the interface of the screen. Check and replace the damaged one. Components can be.

5. If the power supply voltage of the screen line interface is normal, then check the timing signal and drive signal in the LCD panel drive circuit. If it is not normal, check the output signal, the input signal and the supply voltage of the chip that generates this signal to determine whether the driver chip is damaged. If it is damaged, replace it.

Through the above understanding, is there a preliminary understanding of the phenomenon of white screen on the LCD screen? The maintenance of the white screen of the display is not as easy as the black screen of the display. The most insured way to know the circuit of the display is to ask a more professional person to help you find the cause.