LCD TV white screen troubleshooting, what s going on with LCD TV white screen

The white screen of the TV may be caused by the screen cable falling off; The fuse of the circuit board is blown and the picture tube of the TV is fused, the components in the TV are aging, the positive and negative voltage of the liquid crystal display is insufficient, and the reception signal of the TV is abnormal.

The TV screen is white but there is a sound phenomenon,At this time, you should first check the plug-in situation behind the TV,Whether each wire is plugged in at the position where it should be plugged in,And carefully confirm that the contact at the socket is good、There is no loose connecting cable。

The problem that the TV suddenly goes white and won't turn on. In this case, first of all, it is necessary to rule out whether it is due to the connection problem of the power supply caused by the power supply white screen, check whether the indicator light of the power supply is on, if it is not on, check whether the power socket is loose, if not, it needs to be sent to the maintenance center for maintenance.

There are several reasons for this:

1. The LCD TV screen cable falling off will cause the LCD TV to appear white screen.

2. The fuse of the circuit board of the LCD TV screen will also lead to the appearance of the white screen of the LCD TV.

3. There is a problem with the picture tube on the LCD TV's display.

4. The screen power conversion circuit of LCD TV is faulty, and there may be a short display or no display when the screen power supply fails, and then a white screen will be generated.

5. The white screen phenomenon caused by insufficient positive and negative power supply voltage of the LCD screen.

6. Abnormal signal will also lead to a white screen phenomenon on LCD TV.

Suggested Treatment:

1、LCD TV screen line falling off will lead to the phenomenon of white screen on LCD TV,This phenomenon is usually just a small fault,When overhauling, you only need to check which line of the TV is loose,Plug it in again。

2. The fuse of the circuit board of the LCD TV screen can also lead to the phenomenon of white screen of the LCD TV, and the screen circuit board of the LCD TV needs to be replaced.

3. If there is a problem with the picture tube on the LCD TV's display, you can contact the after-sales service of the TV to solve the problem. 4. The screen power conversion circuit of the LCD TV is faulty, that is, the DC-DC circuit is faulty, for example, the voltage regulator is damaged.

You need to contact the maintenance worker or after-sales service for replacement.

5. If it is a white screen phenomenon caused by insufficient positive and negative power supply voltages of the LCD screen, the fault can be solved as long as the voltage is kept stable.

6. If the signal is abnormal, you can move the position of the TV to improve the signal or add a signal booster.

The white screen is the backlight that has no image normally, and the screen itself. There is a problem with the screen cable and driver board.

White screen reason.

1. The screen line falling off will lead to the phenomenon of a white screen on the LCD TV, usually this is just a small fault, and you only need to check which line is loose when overhauling, and plug it back in.

2. The fuse of the TV screen circuit board will also lead to the appearance of the LCD TV white screen phenomenon, and then it is necessary to replace its screen circuit insurance.

3. There is a problem with the picture tube on the display of the TV.

4. The fault of the screen power conversion circuit is the DC-DC circuit, such as the voltage regulator is damaged, and sometimes there is a short display or no display and then a white screen when the fault occurs.

5. The motherboard control chip of the TV monitor is poor or damaged.

6. The components of the TV have been aged, and this phenomenon is usually caused by capacitance problems.

7. The problem of insufficient positive and negative power supply voltage in the LCD screen will also lead to the appearance of the white screen phenomenon, and the stable fault of the main maintenance voltage can be solved.

8. The white screen phenomenon occurs due to abnormal signals.

If the white screen of the LCD TV is just a small fault, we can repair it ourselves, but usually the TV is not something we can solve by ourselves when it fails, when encountering such a situation, it is recommended that you turn off the TV first, to avoid the main board burning out when the TV is running, and at the same time contact a special maintenance personnel to repair it at the same time.

White screen workaround.

One. LCD TV has a white screen,It means that the TV backlight board is operating normally,You should first judge whether the motherboard is working normally,You can press the power switch to check whether the indicator light is reflected,If the indicator light is on,And change the color,It means that the motherboard is working normally。

1.Check whether the connection cable of the motherboard signal output to the screen is in poor contact (the connection cable or screen can be replaced).

2.Check whether the voltage of each working point of the motherboard is normal, especially the power supply voltage of the screen.

3.Use an oscilloscope to check the traveling field signal and the clock (from input to output).

Generally speaking, except for some brands and models of LCD screens that cannot be repaired later due to design reasons (such as HTL7EL2-200, LML70EGOL, etc.), as long as there are some components of each item (see the appendix for the list of common and vulnerable screen display circuit components), the white screen fault can be manually and quickly repaired. If the screen display board and driver board are damaged, there will be a white screen, and we will analyze the causes of its formation and the methods to repair it separately.

1) Driver board failure: First of all, you can use the general driver board instead of the original driver board to observe the image effect, if the image is restored, it means that the original driver board is faulty, check the process: whether the power supply voltage of the screen cable interface is normal (there is generally a fuse resistor or fuse inductor near the VCC output end of the screen line, be sure to check whether it is open), Whether the MCU hardware and internal drivers are normal (AOCL5 inch and its OEM Lenovo 15 inch have a large number of white screen faults caused by MCU damage, MCU model ALIM6759), whether the hardware surface temperature of MCU and ADIC is abnormal, whether the oscillation waveform of ADIC is normal, whether the TTL-LVDS conversion IC power supply voltage is normal, and finally the MCU and ADIC can be fully repaired.

3) LCD screen or screen display substrate failure: This problem is generally due to the driving voltage of the screen, resulting in no power supply for each load of the screen display substrate. There is a separate DC-DC voltage conversion circuit on the LCD screen display board, which is used to convert a low-voltage DC input of the driver board into multiple low-voltage or negative voltage DC, and the circuit principle is similar to that of a switching circuit circuit.

A power management IC is used for pulse width control, and the MOS transistor and inductor coil are used for energy conversion. We can use the idea of repairing the power strip to check the repair. Repair process:

Whether the fuse (F) of the screen display substrate (F) is open, whether the voltage is normal, whether the input and output voltage of the DC-DC conversion circuit is normal, whether the power supply voltage of the screen IC is normal, whether the screen IC is a vulnerable model, and whether the negative voltage formation (-7V) of the DC circuit is OK.

Dear, the above is the relevant answer to your questions about the white screen of the LCD screen [give force] [give force] [give force].

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LCD TV white screen fault repair TV is indispensable in our lives, with the TV used for a long time, so it is inevitable that there will be some problems. Today, I will introduce to you the repair method of TV screen failure.

1.TVs have vertical bars — The reason why TVs have vertical bars.

When you find that there are vertical black bars on the TV screen, check the proportion of the vertical black bars on the TV screen to the entire TV. If there is one red line and two green lines on the morning surface of the black bar, 14 COF lines are driven. According to the display principle of the plasma display, it was preliminarily determined that a COF line driven by a logic board or address was invalid.

Further experiments have shown that by disconnecting the LVDS cable, the entire screen turns black, but there is still one red line and two green lines corresponding to the original black bar. It is now certain that COF lines driven by logical boards or addresses are invalid. Carefully disassemble the COF plug corresponding to the black bar, there is no abnormality, reinstall the COF cable, and the fault disappears.

In order to ensure the reliability after repair, the same failure occurs after one day of continuous observation. Replacing the motherboard is invalid. Once the entire screen is replaced, the fault is eliminated.

COF is an address-driven flexible cable for a plasma display containing a driver integrated circuit. COF and the screen are an inseparable whole, so only the entire screen can be repaired.

2.The TV has a vertical bar - the maintenance of the TV screen.

Measure whether the clock output of the motherboard is normal, and check whether the motherboard signal is input into part of the circuit of the main chip (whether there is false soldering, short circuit, capacitor resistance and whether there is an error value).

Check whether there is a false solder or short circuit in the part of the circuit from the motherboard signal output to the connector output to the screen (integrated circuit pins, drains and sockets, double row pins), pay special attention to the flat socket, and replace the screen or replace the universal driver board if necessary.

3.The TV has a vertical bar - the repair of the white screen of the TV.

The white screen phenomenon of the TV indicates that the backlight plate can work properly. First, determine if the motherboard can work properly. Press the power switch and see if the indicator light responds in any way.

If the light can change color, the motherboard is working properly. Check whether the cable that outputs the motherboard signal to the screen is not in good contact (the cable or screen can be replaced). Check whether the voltage at each operating point of the motherboard is normal, especially the power supply voltage of the screen.

Use an oscilloscope to check the line field signal and the clock signal (from input to output) and write the program with a universal board tester instead of it.

The failure of the LCD TV white screen may be caused by the following reasons:

1.Faulty TV screen backlight: If the TV screen backlight is faulty, it can cause the screen to become very bright, or even completely white. At this point, the backlight needs to be replaced.

2.Faulty TV motherboard: If the motherboard of your TV fails, it may cause your TV to have a white screen failure. At this point, the motherboard needs to be replaced.

3.TV screen failure: If the TV screen itself fails, it can cause the TV to have a white screen failure. At this point, the screen needs to be replaced.

Fixes:1Check whether the TV backlight is faulty, if it is vertical, you need to replace the backlight.

2.If the TV's motherboard fails, the motherboard needs to be replaced.

3.If the TV screen is faulty, the screen needs to be replaced.

It should be noted that the above repair methods need to be operated by professionals, and it is not recommended to try to repair them on your own. If you are not familiar with TV repair, it is recommended to contact a professional TV repairer for repair.

Hello,Common possible reasons for the white screen of the TV:1、The screen line falls off,Knowing that the volt indicator will be white,When overhauling, you only need to check which regret Changtiao line is loose,Re-plug it,Involve disassembly and maintenance,Avoid causing greater failures,Unnecessary losses,It is recommended to find professional maintenance personnel; 2. If there is a capacitance problem, the characteristics of the main chip controlled by the display motherboard are poor or damaged, please contact the maintenance personnel to replace it; ~

This situation is generally due to the screen display line falling off、The failure of the TV motherboard causes the LCD TV screen to display a white screen,It is necessary to confirm whether the TV motherboard is in normal operation and the white screen is judged,If the embedded motherboard works normally,Then check whether the connection between the TV signal lines is matched。

1、When the signal output line of the TV motherboard is connected to the TV screen display cable, if the connection line is wrong,Then the TV will also have a white screen,Because the TV can't receive the signal and can't get out of the picture,Or because of poor contact,Look at the inspection carefullyAt the same time, you can also repeatedly plug and unplug and bend which wiring to carry many times to test。

2. If the fuse of the TV screen circuit board is blown because of high temperature, it will also lead to the white screen of the TV, sometimes because the manufacturer is in production, soldering a few less capacitors, then it is necessary to replace the new fuse wire, the TV components will be aging because of the problem of time, and the aging problem is generally that the capacitance will be abnormal, and it is necessary to pay attention to replacing the new capacitor in time.

3. The screen power supply displays a white screen because of circuit failure, because the voltage regulator is damaged and cannot be used normally, when the TV voltage regulator fails, sometimes it is a short white screen, and there will be no display after a long time, when the voltage regulator is found to be faulty, it is necessary to replace it with a new one in time to avoid damage to other parts of the TV.

This situation is generally due to the fact that the screen display line falls off、The failure of the TV motherboard causes the LCD TV screen to display a white screen,It is necessary to confirm whether the TV motherboard is in normal operation and there is a white screen judgment,If the motherboard is working normally,Then check whether the connection between the TV signal lines is right。 1. If the signal output line of the TV motherboard is plugged in with the TV screen display cable, then the TV will also have a white screen, because the TV cannot receive the signal and cannot get out of the picture, or because of poor contact, it is necessary to check carefully, and at the same time, you can repeatedly plug and unplug the cable to test. 2. If the fuse wire of the TV screen circuit board is blown because of high temperature, it will also lead to the white screen of the TV, sometimes because the manufacturer is in production, soldering a few less capacitors, then it is necessary to replace the new fuse wire, the TV components will be aging due to the problem of time, and the aging problem is generally that the capacitance will be abnormal, and it is necessary to pay attention to replacing the new capacitor in time.

3. The screen power supply displays a white screen because of circuit failure, because the voltage regulator is damaged and cannot be used normally, when the TV voltage regulator fails, sometimes it is a short white screen, and there will be no display after a long time, when the voltage regulator is found to be faulty, it is necessary to replace it with a new one in time to avoid damage to other parts of the TV.