After a certain period of time, smart TVs in the home will have this or that small problem. Some of them can obviously fix it by themselves and sell it after unwittingly. This post is a summary of the experience of television maintenance personnel, it is worth collecting!
First, determine the fault:
To repair the LCD must learn to judge that part is faulty, this is the first step. The following talk about the main LCD TV fault and the location of the judgment.
1: no noise appears on the boot, the power light flashes into a constant light, the screen flashes white light during the boot moment. This fault is mostly the backlight driver board is damaged. However, in the maintenance also encountered is the lamp inside the screen is damaged .
2: After the start of a splash screen (mosaic), the sound is normal. This phenomenon is the first one is a bad digital board (vias or IC contact is not good). The second is the connection between the machine is not good.
3: Power on three, power light is off. The first is bad power board, the second is that the CPU part is not working properly.
4: The light does not turn on: The CPU bus is not working properly or the booting program IC (BIOS) is bad, and there is a bad connection between the "BIOS" IC and the CPU.
Second, maintenance ideas:
1 monitor without electricity
(1) Power failure:
This is a fault that should be said to be a very simple one. The general LCD monitors have both internal and external power supplies. Regardless of the type of power supply, its structure is much simpler than the power supply of crt displays. The fragile components are generally small components such as fuses, rectifier bridges, 300V filter capacitors, power switch tubes, power management ICs, rectifier output diodes, and filters. Capacitance and so on. The power board is commonly used ic:6841 203d06, these commonly used pmw chips can be purchased in my professional LCD accessories shop.
(2) Driver board failure:
Drive board burn insurance or regulator chip failure, some of the machine is to switch power supply built-in, output two sets of power, one set is 5V for signal processing, the other set is 12V to provide high voltage board point backlight, if Some faults in the circuit of the switching power supply may result in no output of the two power supplies. The first check of whether the 12V voltage is normal, followed by checking whether the voltage of 5V is normal, because the operating voltage of the MCU chip of the A/D driver board is 5V, so the search is turned on. Can't fail the machine, use the multimeter to measure 5V voltage first, if there is not 5V voltage or 5V voltage becomes very low, then one kind may be the input stage of the power circuit There is a problem, that is to say the power supply part that 12V changes to 5V goes out The problem, this kind of fault is very common, check the 5-terminal regulator block (common model 8050SD-LM2596-AIC15-01, etc.).
Another possibility is that the 5V load is getting heavier, and the 5V voltage is pulled very low. In other words, the signal processing circuit in the rear stage has a problem, some of the circuits are damaged, and the load is aggravated, pulling the 5V voltage. Very low, one by one after the investigation of the problem of the components after the problem, replace the failed components, 5V can return to normal, the fault is generally resolved, but also often encountered after the 5V voltage returned to normal can not normally boot, this situation is also more One reason is that on the one hand, the MCU program is flushed, which may cause no boot, and the MCU itself is damaged. For example, the I/O port of the MCU is damaged, so that the MCU cannot scan the buttons, and this type of failure caused by the MCU is encountered. The problem of finding the hardware is useless, even if you change the MCU can not solve the problem, because the MCU is the need to program and write code, in the case of no way to find the original AD driver board replacement, we can only use the general A/D driver board substitution such as: 151D or 161B.
2. The display will not light up, but the power indicator will light green.
This kind of problem is generally caused by high voltage abnormality, and it is the protection circuit action. In this case, the LCD screen is generally displayed, and the method of viewing is “strabismusâ€.
3 black screen, no backlight. Power light green light.
Strabismus LCD display images, mostly high-voltage board power supply circuit problems. Focus on checking the 12V power supply (Fuse F) and 3V or 5V switch voltage is normal. If there is no output switch control voltage due to MCU problems, you can directly extract the 3 terminal stability The (AIC1084)3.3V of the briquette replaces the idea of ​​repairing the high-voltage board (power fuse----switch control tube----power management IC---- push-pull bulk----power switch-- - DA conversion circuit (energy storage inductors, rectifiers) --- LC boost circuit (step-up transformer, boost capacitor) ------ coupling capacitor - light.
4. The screen is bright, bright or dark
This problem is generally a fault of the LCD screen.
The bright line fault is usually caused by the problem of the cable connecting the LCD panel body or the damage of the driver IC of a row and column.
The dark line is generally the body of the screen has leakage, or TAB flexible board connection open. The above two problems basically is to sentence the machine to death, there is no maintenance value, because the price of a screen is too high.
5. Huaping or white screen
This problem is generally a problem with the driving voltage of the screen. First, the driver board and the driving line test are replaced. If not, the maintenance concept is as follows: Driving plate 5V to 3.3V regulator block (AIC1084)
Is there a power supply output. --- Screen driver board fuse (F) - 3.3V ----- DC-DC converter circuit - Negative pressure forming IC (-7V) - Row, column driver IC .
AAT1101A M150XN05 screen power management chip, after the damage is displayed as a white screen' boot image dimmed
AAT1164 M170EG01 new screen-pass disease, mainly used in BenQ FP71G + LCD above. With a period of time will be a blank screen, shut down in the opening for a period of time and then there is a white screen. This chip for the LCD screen high voltage generation and management chip, BenQ LCD monitor often bad, fault: white screen.
6. Color cast failure
Generally can enter the factory adjustment mode to adjust. Without this model, maintenance ideas: replace the screen line and adapter plate ----- rewrite the driver ----- driver board is bad (uncommon) ----- the screen backplane control IC is bad (not Common) -------- Unplug the screen to observe the backlight color (backlight flat color lamp aging) ------- change lamp.
7. Character virtual or trailing
Maintenance ideas: Check the VGA signal line, focus on the RGB three-color ground wire is connected to the normal ----- replace the screen line or adapter plate ----- rewrite the driver ----- for the driver board - ---LCD screen backplane signal interface IC bad ----- LCD screen backplane contrast potentiometer adjustment ------ LCD screen light guide plate misalignment - polarizer dislocation
8. The inside of the LCD screen is stained
Maintenance ideas: Wipe or replace the protective film ----- open the screen to clean the outer polarizer and plexiglass (with cotton balls, purified water treatment) --- hair dryer blow dry
9. LCD screen leaks or uneven light
Maintenance ideas: re-install the lamp ----- adjust the light guide plate
10: LCD screen highlights
One or two large bright spots, you can try to lightly press the bright spot with your fingertips, can disappear, indicating more than this pixel pixel switch and electrode virtual connection. Small black spots and gray spots may be internal light guide plate or polarized light Dust caused by tablets. Can be cleaned.
11: LCD screen brightness is low
Check the high-voltage board ADJ brightness adjustment circuit----------Change the lamp--------Change the high-pressure board--------Adjust or replace the light guide plate
12: Error message "Out of frequency range"
Check the signal line ------- Rewrite the MCU driver ------- Replace the EPROM ------- Rewrite the EPROM program -- Change the driver board
13: After turning on the power, the backlight will not appear on the white screen without pressing the switch button. After pressing the button, the image can be displayed normally.
High-voltage board interface switch signal and ADJ signal reverse connection caused, part of the driver board MCU switch signal output is not normal, you can rewrite the MCU program to repair .------- change MCU
14: Addition, the lamp size needs to be clarified when the lamp aging screen is changed. Because the screen size is the same, the lamp length and thickness are slightly different. If the same size lamp cannot be found, It is better to use a short lamp. If it cannot be used, use a scalpel to carefully remove the screen frame from the slightly longer lamp and use a heat-shrink tube to insulate it.
Smart TV/box information can focus on smart TV information network sofa butler (http://), China's influential TV box and smart TV website, providing information, communication, TV boxes, smart TVs, smart TV software, etc. Answering questions.
First, determine the fault:
To repair the LCD must learn to judge that part is faulty, this is the first step. The following talk about the main LCD TV fault and the location of the judgment.
1: no noise appears on the boot, the power light flashes into a constant light, the screen flashes white light during the boot moment. This fault is mostly the backlight driver board is damaged. However, in the maintenance also encountered is the lamp inside the screen is damaged .
2: After the start of a splash screen (mosaic), the sound is normal. This phenomenon is the first one is a bad digital board (vias or IC contact is not good). The second is the connection between the machine is not good.
3: Power on three, power light is off. The first is bad power board, the second is that the CPU part is not working properly.
4: The light does not turn on: The CPU bus is not working properly or the booting program IC (BIOS) is bad, and there is a bad connection between the "BIOS" IC and the CPU.
Second, maintenance ideas:
1 monitor without electricity
(1) Power failure:
This is a fault that should be said to be a very simple one. The general LCD monitors have both internal and external power supplies. Regardless of the type of power supply, its structure is much simpler than the power supply of crt displays. The fragile components are generally small components such as fuses, rectifier bridges, 300V filter capacitors, power switch tubes, power management ICs, rectifier output diodes, and filters. Capacitance and so on. The power board is commonly used ic:6841 203d06, these commonly used pmw chips can be purchased in my professional LCD accessories shop.
(2) Driver board failure:
Drive board burn insurance or regulator chip failure, some of the machine is to switch power supply built-in, output two sets of power, one set is 5V for signal processing, the other set is 12V to provide high voltage board point backlight, if Some faults in the circuit of the switching power supply may result in no output of the two power supplies. The first check of whether the 12V voltage is normal, followed by checking whether the voltage of 5V is normal, because the operating voltage of the MCU chip of the A/D driver board is 5V, so the search is turned on. Can't fail the machine, use the multimeter to measure 5V voltage first, if there is not 5V voltage or 5V voltage becomes very low, then one kind may be the input stage of the power circuit There is a problem, that is to say the power supply part that 12V changes to 5V goes out The problem, this kind of fault is very common, check the 5-terminal regulator block (common model 8050SD-LM2596-AIC15-01, etc.).
Another possibility is that the 5V load is getting heavier, and the 5V voltage is pulled very low. In other words, the signal processing circuit in the rear stage has a problem, some of the circuits are damaged, and the load is aggravated, pulling the 5V voltage. Very low, one by one after the investigation of the problem of the components after the problem, replace the failed components, 5V can return to normal, the fault is generally resolved, but also often encountered after the 5V voltage returned to normal can not normally boot, this situation is also more One reason is that on the one hand, the MCU program is flushed, which may cause no boot, and the MCU itself is damaged. For example, the I/O port of the MCU is damaged, so that the MCU cannot scan the buttons, and this type of failure caused by the MCU is encountered. The problem of finding the hardware is useless, even if you change the MCU can not solve the problem, because the MCU is the need to program and write code, in the case of no way to find the original AD driver board replacement, we can only use the general A/D driver board substitution such as: 151D or 161B.
2. The display will not light up, but the power indicator will light green.
This kind of problem is generally caused by high voltage abnormality, and it is the protection circuit action. In this case, the LCD screen is generally displayed, and the method of viewing is “strabismusâ€.
3 black screen, no backlight. Power light green light.
Strabismus LCD display images, mostly high-voltage board power supply circuit problems. Focus on checking the 12V power supply (Fuse F) and 3V or 5V switch voltage is normal. If there is no output switch control voltage due to MCU problems, you can directly extract the 3 terminal stability The (AIC1084)3.3V of the briquette replaces the idea of ​​repairing the high-voltage board (power fuse----switch control tube----power management IC---- push-pull bulk----power switch-- - DA conversion circuit (energy storage inductors, rectifiers) --- LC boost circuit (step-up transformer, boost capacitor) ------ coupling capacitor - light.
4. The screen is bright, bright or dark
This problem is generally a fault of the LCD screen.
The bright line fault is usually caused by the problem of the cable connecting the LCD panel body or the damage of the driver IC of a row and column.
The dark line is generally the body of the screen has leakage, or TAB flexible board connection open. The above two problems basically is to sentence the machine to death, there is no maintenance value, because the price of a screen is too high.
5. Huaping or white screen
This problem is generally a problem with the driving voltage of the screen. First, the driver board and the driving line test are replaced. If not, the maintenance concept is as follows: Driving plate 5V to 3.3V regulator block (AIC1084)
Is there a power supply output. --- Screen driver board fuse (F) - 3.3V ----- DC-DC converter circuit - Negative pressure forming IC (-7V) - Row, column driver IC .
AAT1101A M150XN05 screen power management chip, after the damage is displayed as a white screen' boot image dimmed
AAT1164 M170EG01 new screen-pass disease, mainly used in BenQ FP71G + LCD above. With a period of time will be a blank screen, shut down in the opening for a period of time and then there is a white screen. This chip for the LCD screen high voltage generation and management chip, BenQ LCD monitor often bad, fault: white screen.
6. Color cast failure
Generally can enter the factory adjustment mode to adjust. Without this model, maintenance ideas: replace the screen line and adapter plate ----- rewrite the driver ----- driver board is bad (uncommon) ----- the screen backplane control IC is bad (not Common) -------- Unplug the screen to observe the backlight color (backlight flat color lamp aging) ------- change lamp.
7. Character virtual or trailing
Maintenance ideas: Check the VGA signal line, focus on the RGB three-color ground wire is connected to the normal ----- replace the screen line or adapter plate ----- rewrite the driver ----- for the driver board - ---LCD screen backplane signal interface IC bad ----- LCD screen backplane contrast potentiometer adjustment ------ LCD screen light guide plate misalignment - polarizer dislocation
8. The inside of the LCD screen is stained
Maintenance ideas: Wipe or replace the protective film ----- open the screen to clean the outer polarizer and plexiglass (with cotton balls, purified water treatment) --- hair dryer blow dry
9. LCD screen leaks or uneven light
Maintenance ideas: re-install the lamp ----- adjust the light guide plate
10: LCD screen highlights
One or two large bright spots, you can try to lightly press the bright spot with your fingertips, can disappear, indicating more than this pixel pixel switch and electrode virtual connection. Small black spots and gray spots may be internal light guide plate or polarized light Dust caused by tablets. Can be cleaned.
11: LCD screen brightness is low
Check the high-voltage board ADJ brightness adjustment circuit----------Change the lamp--------Change the high-pressure board--------Adjust or replace the light guide plate
12: Error message "Out of frequency range"
Check the signal line ------- Rewrite the MCU driver ------- Replace the EPROM ------- Rewrite the EPROM program -- Change the driver board
13: After turning on the power, the backlight will not appear on the white screen without pressing the switch button. After pressing the button, the image can be displayed normally.
High-voltage board interface switch signal and ADJ signal reverse connection caused, part of the driver board MCU switch signal output is not normal, you can rewrite the MCU program to repair .------- change MCU
14: Addition, the lamp size needs to be clarified when the lamp aging screen is changed. Because the screen size is the same, the lamp length and thickness are slightly different. If the same size lamp cannot be found, It is better to use a short lamp. If it cannot be used, use a scalpel to carefully remove the screen frame from the slightly longer lamp and use a heat-shrink tube to insulate it.
Smart TV/box information can focus on smart TV information network sofa butler (http://), China's influential TV box and smart TV website, providing information, communication, TV boxes, smart TVs, smart TV software, etc. Answering questions.