TV Repair TV Repair
First, if there is a certain amount of basic knowledge of electronics, electrical engineering, then the basic principles of the TV is not difficult to understand and master, you can learn or ask the master to quickly get started, and gradually accumulate knowledge and experience in practice; Second, learn the basic principles of the TV, you can start to get involved in the maintenance; just started to find some maintenance reference materials, such as "TV Repair Book", "TV Troubleshooting Repair" and so on, there are many kinds of fault phenomena and solutions to the above. At the beginning you can find some maintenance reference materials, such as "TV repair book", "TV troubleshooting maintenance" and so on, there are many kinds of failure phenomena, as well as the solution to these failures, they are other people's efforts and experience cohesion, often can effectively solve the maintenance problems encountered in the maintenance of the TV. Often can effectively solve the problems encountered in the maintenance; in fact, the books are teachers or masters; Third, as for the TV failure is not good maintenance, this question is not a good answer, because anything has a degree of difficulty; sometimes repair a seemingly large problem of the TV, but after checking, it turns out to be just an electronic component soldering, or a plug is not plugged in tightly; and sometimes a seemingly simple problem, only after opening the TV shell found that there is a problem of the TV. After opening the TV shell only to find that there are soft faults (such as poor heat dissipation, poor chip characteristics, capacitor leakage is serious), need to spend a lot of time to overhaul; Fourth, the current TV sets are mainly "tube type" and "liquid crystal", "Plasma", their power supply principle is basically the same, but the display mode, the imaging principle is very different, so to speak, CRT and LCD is almost completely different from the two disciplines; therefore, it is recommended that the owner of the first from the simple CRT type to learn from, and then slowly dabble in the LCD, plasma, etc.; V. Maintenance of the Precautions are: 1, careful, "no power to see when there is power", do not hands (into the circuit) contact with the power supply within the machine; 2, simple questioning, like a doctor to see a doctor, first of all to ask about the condition of the initial understanding of the disease and its basic conditions, and then to have a basic understanding of the fault; 3, carefully look at the start of the TV set Power, to carefully observe the screen, power indicator and other brightness, flicker; while listening carefully to the machine whether there is a murmur or noise; six, maintenance tools and equipment Maintenance needs to be used: oscilloscope, multimeter, soldering iron, tweezers, cross screwdriver, screwdriver, and other tools and equipment; as for spare parts, generally do not need to have inventory, are based on different TV models temporarily purchased need to replace the spare parts; seven, the difficulty of repair issues. Spare parts; seven, repair difficulty 1, induction cooker repair master said, induction cooker is very easy to repair; 2, TV repair master said, TV is not difficult to repair; electrical engineers said, induction cooker, TV, air conditioning, etc., are not difficult to repair, as long as you master their principles and basic maintenance knowledge.
What does the repair process of a TV set include?
〈 A 〉 Television is a very complex machine.
Especially now that the production of television, that is, the degree of integration of the viewing equipment, some of the entire machine, including microprocessors, there is only a piece of integrated circuit. In principle, the TV set can include the following parts: 1, power supply.
The power supply is the most important part of the entire television, it is responsible for the entire television set to provide energy for all parts of the heavy responsibility. Its workflow is the first 220-volt AC converted to about 300-volt DC for the switching power supply; switching power supply is the rectified 300-volt DC converted to several voltages: positive 110-volt voltage for the line output stage; positive 26-volt for the field output stage; positive 19-volt for the companion sound circuit.
Positive 19-volt voltage is also after the regulator circuit output positive 12-volt, for high-frequency head, signal processing integrated circuits; but also the output of positive 5-volt voltage for microprocessor use. Positive 110-volt voltage but also through the buck, voltage regulator circuit output positive 33-volt voltage, for the high-frequency head station selection.
2, high-frequency head. High-frequency head is a TV signal into the door of the TV.
From the antenna or cable TV terminal box into the TV signal preferred into the high-frequency head, after the high-frequency head of the TV signal we need to select the processing and turn it into a TV easy to amplify the intermediate frequency signal and delivery to the intermediate frequency amplifier circuit. The high-frequency head is bad, the TV will not receive TV signals, of course, will not produce images.
But the stronger bath wave point. 3, the IF amplifier circuit.
The IF amplifier circuit sends the high-frequency head we need to amplify the IF TV signal to a certain amplitude, and the image signal and the accompanying audio signal is sent separately, the image signal is sent to the video (i.e., image) amplifier to amplify the enlarged image signal is added to the picture tube, so that it displays the image signal we want to see; accompanied by the audio signal is sent to the audio power amplifier and promote the loudspeakers (speakers) to release the sound. The accompanying audio signal is sent to the audio power amplifier and drives the speakers (horns) to emit sound. IF amplifier and video amplifier circuits are currently centralized in an integrated circuit, such as the commonly used LA7680, LA7685 and so on.
By the high-frequency head output of the intermediate frequency television signal to it, it will send the image signal directly to the picture tube; the accompanying audio signal to the accompanying audio amplifier circuit. In addition, this integrated circuit has to output field and line oscillation signals, and sent to the corresponding amplifier circuit.
4, line output circuit. Sent by the integrated circuit of the line oscillation signal amplification, and through the line output transformer to produce a variety of voltages required by the picture tube.
The use of the line output circuit has the following: A, the output of high-voltage, high-frequency pulse voltage, sent to the line deflection coil, the formation of a sawtooth wave voltage by the deflection coil, so that the electron beam for the horizontal movement in the tube's screen to form a horizontal bright line; B, the output of 25,000 volts of high voltage DC, supplied to the anode of the tube to make the tube's anode has to attract the cathode of the electrons emitted by the role of the tube to make the raster; the tube to issue a grating; and the line output circuit is a high voltage output circuit. C, the output fade voltage, the main purpose is to eliminate the field, line scanning electron beam from left to right scanning back to the scanning bright line. D, the output of 180 volts for the work of the visual amplifier.
E, output 6.3 volts filament voltage, for the picture tube filament heating, and bake the cathode of the picture tube, so that the cathode can emit electrons. G, the output of about thousands of volts, as the tube focusing voltage.
Without the focusing voltage, the image will be blurred. H, output about 500 volts, as the accelerating voltage of the tube.
No acceleration voltage, the tube can not light. 5, field output circuit.
The main role of the field output circuit is to provide the field deflection coil field sawtooth wave voltage, so that the tube's electronic scanning line from the top to the bottom of the movement. This part of the bad, the tube shows only a horizontal bright line.
6, video amplifier circuit. Most of the video amplification circuit in the picture tube on the tailstock, composed of three to five tubes, there is also a piece of integrated circuit, the principle of operation is the same.
The task is to send the video signal from the integrated circuit to amplify, and sent to the picture tube to show the image. Video amplification circuit is bad, the CRT can only show a clean raster, no image, but there will be the sound of the TV station.
One of these tubes is bad, causing the image to lack color. In addition, there are others in the TV set, such as fuses and degaussing circuits.
The fuse is used as an insurance for the whole TV set, if it breaks, the whole set will not be energized, which will result in a failure to turn on the TV. The degaussing circuit contains a degaussing resistor and a degaussing coil.
The degaussing coil is placed on the tube, and is generally not bad, but the degaussing resistor is easy to break. Degaussing circuit is bad, a short time, there will be no effect, but for a long time the picture tube will appear on the messy color patches, or the display of the color is not normal.
〈II〉 The damage rate of the color TV power supply circuit in the TV repair is relatively high, nowadays, none of the color TV power supply circuit is a switching regulated power supply circuit. Switching regulated power supply circuit is roughly divided into parallel type and series type two categories, the oscillation circuit are clear self-excited oscillation circuit, some introduced line synchronization function, some do not have, the principle of switching power supply here, not to say more, mainly to introduce the switching power supply of the main overhaul method.
First, the composition of the switching power supply General switching power supply is composed of oscillator circuit, voltage regulator circuit, protection circuitry composed of three major components. 1. Oscillator circuit: switching power supply oscillator circuit is divided into transistor oscillator circuit and integrated block oscillator circuit, such as STR-S series IC, TEA2104, TDA4601, TDA4605, TDA2261, etc.. 2. Voltage regulator circuit: switching power supply voltage regulator principle are used to pulse-width regulator, that is, by automatically changing the ratio of switching power tubes off and on time, or by changing the duty cycle of the oscillator's output pulse to achieve the purpose of regulating the voltage. Voltage regulator part of the circuit by sampling, comparison, control of three parts, many of the movement of this part of the circuit is the use of IC (such as SE110 and other ICs) and photocoupler combination of parts, while some of the movement is composed of discrete components (mostly domestic), and some of the movement of the power supply IC itself integrated part of the circuit (such as part of the tandem-type switching power supply IC). 3. Protection circuit: color TV switching power supply are equipped with protection circuit, its protection mode is to make the circuit stop vibration. There are over-current protection, over-voltage protection and under-voltage protection (short-circuit protection), as well as overheating protection.
The overcurrent protection circuit of the overcurrent sampling point, most of the TV sets are in the main oscillator power tube emitter potential. The sampling point of the overvoltage protection circuit is generally taken from the 220V AC rectified and filtered voltage or the main load supply.
LCD TV LCD screen repair how much money repair introduction and troubleshooting
LCD TV is now on the market more popular class of products, they not only have a high degree of clarity, and in the picture of the rendering ability of the performance is also very good, and therefore can successfully win the majority of consumers favor, and become one of the products that everyone competing to promote. But after a long time or in some of the wrong way to use, we are likely to encounter such as LCD TV display failure, this time you need to ask the relevant professionals for maintenance. In this case, today I bring you the repair of TV LCD screen charges.
First, the repair of TV LCD screen repair generally how much money
General LCD TV black screen problem, are because of the LCD TV power supply circuit and drive board circuit of some components out of the problem, such as large filter capacitor damage, power switching tube internal short circuit, burn insurance, MCU chip damage, image processing chip damage, power supply regulator circuit, etc., will cause the LCD screen black screen phenomenon. LCD screen black screen phenomenon. General repair how much money, it depends on the bad above which components, if it is a chip, generally in the 150 or so, if it is a switching tube, large filter capacitors, power supply regulator, these are generally in the 80 or so, but because of the differences in the region, may be different.
All of the above prices are from the Internet, only for reference.
In the LCD TV repair, the repair of different TV components when it is different prices, the general repair of LCD TVs, its basic repair costs are 120, 140, 160, 200, 260, 280 yuan, these basic repair costs are defined according to the different repair projects, it is the basic repair projects are: 14-15, 17- 20, 26-30, 32-40, 42-47, 50-52, in the basic repair costs, if the TV is struck by lightning or water after the failure, it is necessary to add 30% of the cost. 14-15 of this basic project in the replacement of the SSB board when it is priced at 70 yuan.
Second, LCD TV repair fault identification
1, LCD TV in the use of the process, if the TV is on without sound and image problems, while the TV power light flashes a little bit after the TV into a long bright, TV in the boot moment flashing white light, the TV failure should be the TV's backlight driver board is damaged, but do not rule out the TV backlight tube problems caused by. The backlight tube problem is caused.
2, the TV after the boot phenomenon of three no phenomenon, no sound, no image power lights do not light. The first factor that causes this failure is that the power supply board should be a problem, and again, it may be because the CPU part of the TV set is not working properly.
3, the phenomenon of TV after the start of the screen, but the TV sound display is normal, leading to the emergence of this factor should be the cause of the TV's digital board is bad, the second factor should be the machine is not good contact with the connecting wire caused by.
4, after the TV light flashes can not boot. This LCD TV fault identification should be the TV's CPU bus is not working properly or poor contact with the LCD TV IC.
Third, LCD TV repair - troubleshooting
1, the TV screen full of dots or screen full of regular vertical bars are generally the TV buffer board problems, this time for LCD TV repair, you can replace a pair of buffer boards, or measure which IC line failure, and then replace it.
2, LCD TV is most likely to appear the problem is the dark band and lines, when the LCD TV when such a problem, in fact, it can be summarized as a problem of the TV display, LCD TV display this phenomenon may be due to the high temperature of the TV led to the LCD TV's COF and the screen between the connecting point of the detachment, this time for the LCD TV repair, you can use a flat head of the soldering iron pad heat insulation. The soldering iron pad insulation medium ironing way to repair.
3, LCD TVs appear to turn on the relevant but after a period of time no light and sound is the case, generally because of the TV screen component inverter circuit failure, in addition to the aging of the TV light tube or damage caused by the TV high-voltage board protection. This repair can be used to cancel the high-voltage board on the average value of feedback to the circuit to determine whether the high-voltage board itself is a problem.
In addition to analyzing the LCD TV repair charges, we have also introduced a few boards from the fault identification method. Through the above professionals point of view, I believe that we can understand the LCD TV failure in accordance with the different forms of specific manifestations, under the banner of a number of classifications, so about the elimination of the steps is crucial. In addition, we also need to master a certain background of the relevant basic knowledge, in order to facilitate the timely resolution of problems that may exist in the LCD TV, in order to prevent the impact of the use.
How to learn to repair LCD TV?
Learning to repair LCD TV method:
First, learn the theory of LCD TV.
Because the first step in troubleshooting is to analyze the fault, you do not know the circuit structure of the LCD TV and signal flow, do not know the voltage supply data of each circuit of the LCD TV, do not know the voltage control circuit of the LCD TV is how to control, you feel that you do not know where to start repair. If you don't learn the basics, you won't be able to fix your LCD TV quickly. You will only be able to repair some apparently simple faults. Repair technology will not be able to update, stay the same, in the future you will face the elimination of this era. So to learn good LCD TV repair technology, we must understand the working principle of the LCD screen, working conditions, and new circuits and new technologies, the application of new components (such as MOS tubes, etc.), only to strengthen the theoretical learning in this area, and accumulate some knowledge of repair technology. Only then will you keep up with the development of electronic technology of the times, only then will you become an excellent LCD TV repairer. You will be respected; you will have endless wealth.
Second, LCD TV repair to have a good repair tools
LCD TV repair to have a digital multimeter, with anti-static thermostatic soldering iron wind gun, oscilloscope. Repair CRT color TV friends will know a 20 feet above the integrated block is bad, with a soldering iron to remove and install the integrated block to more than 30 minutes, with the electric air gun is only about ten minutes, and the welding point will not be damaged. Oscilloscope is an electronic instrument used to display and observe the signal waveform, it can be used to observe and directly measure the signal voltage size and period in the LCD TV, according to the parameters of the detected waveform to determine whether the detected voltage is faulty, but also to improve the speed of maintenance to determine the fault.
Third, to have their own information database
The ancients marching to war, usually before the troops and horses, food and grass first. Want to learn to learn *** crystal TV repair technology, heart must have their own maintenance database. In the maintenance of the actual encounter to data, do not know accessories to buy there, to their own information database to check not know.
LCD TV repair fault identification
LCD TV sets often appear the phenomenon of flicker, that is, after turning on the screen, the screen is bright for a moment and then turn off. But other functions are normal, such as sound, remote control buttons. This phenomenon is mostly due to the LCD screen backlight protection circuit is disconnected, may be due to the backlight voltage abnormalities caused by. Because the most important and valuable components of the LCD monitor is the display, so the protection circuit will be added. Troubleshooting and repair methods are mainly two, one is to check whether the socket connection of the backlight booster board is normal, there is an open weld on the place of welding. The second is that the socket is not plugged tightly, plug tightly on it.
There is also no change in the LCD TV after the power on, other places are normal: sound, remote control, etc.. This fault needs to do the following judgment. First, check the supply voltage of the backlight circuit, the supply voltage is not normal will lead to this phenomenon. General large screen for 24V, small screen for 12V, the TV manual will be labeled. Second, check the switch control signal of the backlight, whether the high level start, whether the signal waveform is normal. General replacement of the boost board can be, boost board replacement failure still can not be eliminated, multi-bit backlight failure.
Liquid crystal TV will also appear after the phenomenon of the screen, this fault judgment has two methods. One is to check whether the digital board contact is normal, not normal, then weld the welding place can be welded. The second is whether there is poor contact within the TV. Repair methods and the same as above. If the TV does not display nor sound, we should check the backlight and sound system, and then gradually determine the fault, and then troubleshooting. After the power on the power light does not light, there may be a power board failure, there may be a CPU failure, and then to judge and then appropriate replacement or repair can be.
Several common failure repair methods of TV
1, Hitachi 2518 color TV at the same time appeared a variety of faults in the repair of a Hitachi 2518 color TV to wait for three minutes after the start-up of the sound and image and image field synchronization is unstable with linear distortion and the phenomenon of the absence of color, open the machine back cover to measure the power supply voltage in addition to the +12V voltage is low 1.5 V outside the rest of the normal, carefully observed that the main circuit board on the main circuit board. Careful observation found that the main circuit board in several places on the wet marks, further observation found that these wet marks are leaked by the electrolytic capacitors on the board, this will be wet marks near the electrolytic capacitors are all new and use alcohol to clean the circuit board, the boot sound back to normal but the image is not colorful, disassembly and inspection of the relevant components have not found a problem, it is suspected that the circuit board by the corrosion of electrolyte leakage, so the circuit board will be re-cleaned with detergent (cleaning) The board should be cleaned with detergent (cleaned by removing the amplifier board and high-frequency head), blown dry with an air blower, and then tried the machine, and the picture and sound were all back to normal.
We have repaired a number of such machines, the failure is similar to this approach to repair, Hitachi 2518 electrolytic capacitor leakage is a common problem. In addition, Hitachi 747 and 757 VCR also has a similar problem, the failure phenomenon is the sound variations and image instability, at this time, as long as the servo IC near the electrolytic capacitors all new and cleaned to eliminate the problem.
2, music TC-2185 color TV (M15L movement) can not open the maintenance of a music TC-2185 color TV open the power switch after the TV is in standby mode (small red light) press the remote control and the keys on the machine are not responsive, the measurement of the CPU power supply voltage is low, and then disconnect the 5V power supply load one by one to check and found that when disconnecting the remote control receiver head when the 5V voltage returns to normal, the remote control receiver head unplugged, the 5V voltage returns to normal. Remove the remote control receiver head, try the machine back to normal, the receiver head will be inserted back to try again, the fault appears, proving that the failure is caused by the receiver head leakage, due to the low 5V voltage makes the CPU can not be reset correctly caused by the failure of the power on, change the receiver head troubleshooting. 3, music 29GF30R (M18 movement) color TV often automatic shutdown repair This TV set in the use of the process of automatic shutdown often occur in the course of the fault, fast 5 minutes to appear fault slow a few hours or even a dozen hours before the fault, we found that after the failure of the indicator light flashes, which indicates that the TV set into the state of self-protection in order to find out the root cause of the problem will be to protect the circuit of the various sampling points one by one Disconnect the protection circuit sampling points one by one (disconnect a point such as not to say the lot of service?). The protection circuit of the TV set is in a state of self-protection in order to find out the source of the problem. What is the reason for this? What is the name of a blossom? What is the name of a family? Can I get a good deal on a new product? The voltage on the badger C bus has a slight jump, suspected by the IC bus control of geometric distortion correction IC: TA8859P has a problem, change, the problem still exists, according to the failure of the IC bus voltage jump phenomenon, check the IC bus IC hooked up to the IC, when checking the storage IC1211 found that the soldering pins on the mildew point, will be cleaned up mildew point and re-soldered for three days of continuous test machine! Failure to occur again, the failure to confirm that has been ruled out.
This fault is more special, the machine into the self-protection state is not caused by the machine's protective circuit action, but the CPU internal self-protection control voltage to make the machine automatically shut down. 4, music TC-29V2H color TV line amplitude increased and appeared pillow-shaped distortion repair First of all measured pillow-shaped distortion correction tube Q710 set motor voltage is only 2V (normal for 12V or so), adjusting the pillow-shaped correction and line amplitude adjustment potentiometer screen are changes, but the amount of correction is very little (so then the pillow-shaped correction tube working voltage is only 2V, almost work in the saturation state), which indicates that the pillow-shaped correction tube is not a problem, but it's not a problem. Before the circuit is basically no problem, the problem is in the pillow correction tube after the circuit, measuring parabolic wave forming capacitor C758 (50V 4.7?F) did not find a problem, with an inductance meter to measure the inductance of the choke coil L754, measured as 50?H, obviously this inductor has a problem, because the inductance should be 350-500?H, the inductor will be all the wire removed with the same wire diameter of the The inductors were removed and rewound with the same wire diameter enameled wire and number of turns, and the inductance was measured to be 370?H after winding, and the problem was solved by mounting the test machine.
5, Leroy 21-inch TV soundless repair A Leroy CP5438W color TV, the failure phenomenon for the elephant sound, this TV set of the front companion IC for the TDA8425, which is a piece of IC bus control (including volume, left and right balance, high and low tones) of the sound processing IC, initially suspected that the IC has a problem, the change, the fault is still there. Carefully track the circuit found that this machine has a circuit board, drawings are not marked, this circuit board has a TDA8416 IC, this board has four pin-out, ground, power supply and two IC bus connection feet, overview of this circuit, and IC bus connection is only the two IC and a memory IC, according to fault analysis of the possibility of memory problems is not very likely, so. TDA8416 will be replaced by a new, test machine troubleshooting. 6, Vigor brand 29-inch color TV to escape the maintenance of a Vigor 29-inch color TV to escape the fault, the failure phenomenon is: 30 seconds after the start-up of the image accompanied by the sound are normal, after the image snowflakes increase image distortion and accompanied by a significant increase in noise, and finally a blue screen. Repeat the failure process after the turntable. This machine is a piece of TDA8362 to complete the amplifier, color solution and scanning tasks, check when the image changes when the high-frequency head tuning voltage remains unchanged, which indicates that the failure is not caused by the tuning voltage. Then check the high-frequency head AFT voltage found that this voltage is not stable. Analysis of this machine using the TDA8362 to complete the amplifier, color solution, scanning and other functions, the IC video detector and AFT circuit using synchronous detector circuit form, it is peripheral only a 38MHZ mid-period, adjust the mid-period of the video detector and AFT can be achieved by adjusting the adjustment of the AFT voltage from the 44-pin output, the control of the high-frequency head of the local oscillation.
So the tuning of this machine is selected by the high-frequency head, IF input sound surface filter, 38MHZ in the middle of the week, the three main components, this three components of the parameters of the requirements of the more stringent requirements, the parameters of a part of the change are affected by the quality and stability of the reception. Accordingly, check the video synchronization demodulation in the middle week, did not find a problem, after using the IF signal generator input, when the input frequency of the IF signal for 39MHZ, the image is stable and normal, the frequency of 38MHZ when the image appeared seriously distorted, which indicates that the IF channel frequency characteristics offset 1MHZ, suspected that the IF input side of the acoustic surface filter has a problem, change the fault eliminated. 7.Hitachi CTP215SF power supply can not be vibration repair This TV due to lightning strikes and three no fault, power on the inspection found that the power supply main oscillator tube Q901 and the power supply IC have been damaged, a new power on and found that the 110V mains voltage can not be established, using a multimeter to measure the voltage of the AC rectifier.
I want to learn how to enter the LCD TV repair
First, the LED LCD repair common detection methods
Short-circuit detection method - the multimeter will be adjusted to the short-circuit detection block (generally with an alarm function, such as conduction is issued a chirp), to detect whether there is a short-circuit phenomenon, and the short-circuit should be resolved immediately after the discovery of the short-circuit. After the discovery of short-circuit should be resolved immediately, short-circuit phenomenon is also the most common led display module failure. Some by observing the ic pins and pin pins can be found. Short-circuit detection should be operated in the case of circuit power failure, to avoid damage to the multimeter. This method is the most commonly used method, simple, efficient. 90% of the faults can be detected by this method of judgment.
Resistance detection method - the multimeter will be adjusted to the resistance file, a normal circuit board to detect a point of resistance to ground, and then test another piece of the same circuit board at the same point to test the resistance value with the normal whether there is a difference, if different from the scope of the problem is determined.
Voltage detection method - the multimeter will be adjusted to the voltage file, the detection of suspected problems in the circuit of a point of the ground voltage, compared with the normal value is similar to determine the scope of the problem can be easily.
Voltage drop detection method - the multimeter will be adjusted to the diode voltage drop detection gear, because all the ic is composed of a basic number of units, just miniaturized, so in when it has a pin on the current through the pins, there will be a voltage drop on the pins. Generally the same type of ic the same pin on the voltage drop is similar, according to the voltage drop on the pin to compare the good and bad, must be operated in the circuit under power failure.
Second, the LED LCD repair tools
1, soldering iron + suction gun each 1, a number of solder;
2, 5v regulated power supply 1, to receive the card and the maintenance of the module or unit board power supply;
3, electric batch of 1, used to quickly dismantle the module or the unit board;
4, the computer + send the card, used to receive the card send program;
5, the computer + send the card, used to give Receiving card to send the program;
5, receiving card + hub board, used to observe the module or unit board failure phenomenon;
6, a multimeter, used to detect the module or unit board specific failure;
7, tweezers, scissors, pliers 1 each.
Third, LED LCD repair basic steps
1, to determine the module or unit board using the hub board type, so that the interface definition of the wires can be the same;
2, according to the different types of modules or unit boards, the receiver card to send the appropriate program to ensure that the module and the unit board in the correct program to display, which is a prerequisite to find out the cause of the failure. This is a prerequisite to find out the cause of the problem. General pcb board will be printed on the module or unit board model;
3, observe the module or unit board phenomenon, to determine the initial fault. For example, common blind lights, string points, small square, etc.;
4, use the multimeter to find out the fault, mainly by using the short circuit detection method above, between the chip and the lamp pins;
5, test again.