We will describe how to repair Samsung monitors with your own hands with a malfunction, which is that the device does not turn on, the indicator on the front panel is inactive. Let's consider several damage options.

Disassembling the monitor

Having turned on the monitor to the network, we see that its backlight does not light up, the display periodically tries to show a picture, blinks and does not turn on. In addition, the power light flickers. This indicates that there is a short circuit somewhere in the device, and it goes into protection. Presumably the problem is in the capacitors located in the Samsung monitor circuit.

Let's disassemble the monitor. Unscrew the screws with a flat screwdriver. Try to do this carefully using a metal spatula. There is no need to press hard so that there are no marks left on the plastic.

After snapping off the front frame, turn the monitor over so the matrix is ​​facing down, remove the back cover and turn off the front frame. We remove the wires, snap off and unscrew the metal frame that holds the matrix on four screws.

Next, turn off the backlights by removing them from their sockets. We remove the board by unscrewing the screws. Have you noticed swelling of two electrolytic capacitors? It must be remembered that one or more capacitors in the monitor may swell. Even if this part did not explode or leak, but only slightly increased in size, it is damaged and must be replaced.

The main reason for such a defect is the old age of the capacitors (the hourly operating time may expire). In addition, there may be a defect and the capacitor has dried out. Sometimes this part fails due to voltage surges. Swollen, leaked or exploded capacitors must be dismantled, new ones installed and checked. So, now you know the cause of the breakdown.

Swelling, leakage, explosion of capacitors

We continue to find out how to repair Samsung monitors with our own hands. So, turn on the soldering iron. We pre-lubricate the contacts with flux to ensure better soldering. While the soldering iron is heating up, unscrew and remove the power supply board from the case. Before this, disconnect the cable that goes to the control board. We find the board legs on the back side. When replacing capacitors, it is recommended to replace them all at once. We solder them. We replace the capacitors with exactly the same nominal values. Here, the use of a nominal value with an overestimated operating voltage is allowed, but with an underestimated one, it is prohibited.

You can use a slightly larger capacitor capacity, but within reasonable limits. For example, instead of elements with a capacity of 470 μF, you can install parts with a capacity of 680 μF. And one more thing: it is desirable that the new capacitor is sized to fit in the right place, and the width between the legs matches. We insert new capacitors, not forgetting to observe the polarity, and solder them.

We carefully and carefully proceed to the assembly. We insert the board back into the case. We connect all cables and connectors. We connect the cables and tighten the screws. We assemble before putting on the frame. Then we proceed to a trial intermediate launch. We connect the device to the network for testing. After replacing obviously faulty capacitors, in 90% of cases the defect disappears and the monitor starts working.

Defective power capacitor

Let's consider another variant of a display defect that does not turn on and its power indicator is inactive. And in this case, we will try to repair the Samsung monitor ourselves. You can see the disassembly of the device above. Let's move straight to inspection and identification of defects. So, after examining the power supply, you have identified a defective power capacitor. Electrolyte leaks are visible in the area of ​​the left contact of the capacitor. In this case, the part has lost its seal and requires replacement.

Often, when this capacitor fails, the power transistor burns out, which powers the power supply transformer, as well as the mains fuse. First we check the condition of the fuse and ring it. The fuse is intact. On the capacitor contacts short circuit No. There is no short circuit on the transistor either. We'll make do with a replacement. The damage has been fixed.

Inverter power

Let's look at the following version of the flaw, in which the Samsung monitor does not turn on. In this case, a breakdown will be detected in the inverter power supply or its fuses. We continue to carry out repairs ourselves.

Many people know that the inverter's power goes through a fuse, which is located next to the capacitors. It looks like a resistor in a green case. Often, if the capacitors are faulty, the inverter fuse also fails. We check the serviceability of the fuse with a multimeter in continuity mode. When the fuse checks, the multimeter should indicate a short circuit (if the part is working properly). Our fuse is damaged.

Did your multimeter show an open circuit? It should be noted that the fuse could have blown due to a malfunction of the inverter itself. If so, it will burn again. Therefore, it is necessary to calculate the cause of the inverter malfunction. In this case, you need to check for a short circuit in the inverter power supply to prevent the fuse from blowing again. So, let's install a new fuse. The monitor is working.

Backlight inverter

In this section, we will look at do-it-yourself repair of an inverter malfunction, which was discussed in the previous section. Having determined that the fuse is open, we begin to search for the inverter defect. It is necessary to check the power transistors of two arms for each pair of lamps. An obvious defective capacitor was found at the inverter output. It is darkened, flaking and cracked. There is a possibility that the inverter transistors are working, and the fuse has failed due to overload in the secondary circuit of the inverter.

We still check the transistors. There should be no short circuit between the terminals. All transistors are normal. We replace the faulty capacitor and fuse. We install the board in place, connect the wires, and turn on the monitor. There is an image.

Assembly

The article discusses only some episodes of do-it-yourself repair of Samsung monitors. What do experts say about this technique? Many technicians believe that Samsung monitors are susceptible to the above breakdowns. Reviews from repairmen about this equipment continue to be positive.

Hi all!

So, I went in for repairs.LCD monitor KTS 9005 L, Chinese (probably) made.

The malfunction was trivial - the monitor did not turn on , the standby indicator blinked green. He blinked randomly, without any specific interval.

Because this monitor fed from an independent source ( power unit 12B 4A), then the first thing I did was measure output voltage of this power supply, which instead of the required 12V was about 6V.

Well, that's the reason for the inabilitylcd monitor , I thought and began to “open” power unit , to find out the reasons for this behavior of the source.

After the “opening”, faulty output capacitors were discovered - 1000 and 470 microfarads 16V and 100 microfarads 25V, which were successfully replaced.

After the procedure, power unit It started working in normal mode and began to produce the required 12V.

I then connected a working power supply to the monitor and, hoping for the best, turned on the monitor.

But... in general, my hopes were not justified and I still had to open the monitor for further diagnostics, which, in fact, is what I did.

During a visual inspection, nothing suspicious was found. After that, I measured all the voltages that are available in this monitor, namely 12V, 5V and 1.8V. The voltages were slightly underestimated, just a little. Well, since this is the case, I decided to check the capacitors at the 12V input and set about it. The capacitors turned out to be faulty, and what a fault. Measuring capacitors esr meter, it turned out that the device does not even detect these capacitors as capacitors. Then I decided to check the remaining electrolytes in the circuit and on the inverter board. Imagine my surprise, after such a check... It turned out that literally ALL electrolytic capacitors were out of order. Moreover, these elements were not identified by the device as capacitors:either not defined at all, or defined as other elements.

I explained this malfunction to myself as follows: this monitor was used with a CCTV camera and was constantly in working condition. If it were turned off for a while, then if a couple of electrolytes failed the next time it was turned on, the monitor simply would not turn on. But since it was constantly in operating mode, it turned off only when the power source began to supply less voltage.

Well, in general, that's it! DIY LCD monitor repair took place.

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If your monitor is broken and doesn't work, you can try to repair it yourself, gaining useful practical skills and saving money on your wallet. What do we need for this? Firstly, you must have at least minimal knowledge in the field of electronics and electrical engineering. Secondly . And finally, to successfully repair a computer monitor, you need to know its structure and the operating principle of various electronic components of a modern monitor. In addition, you need to be able to do it so that you can assemble it later. So, let's begin.

It’s enough just to look at the monitor and understand that this is a complex device consisting of different nodes and blocks. As you immediately notice, the main component of a modern monitor is a liquid crystal panel or matrix.

LCD monitor matrix repair

The LCD matrix of a monitor is usually a ready-made device; if it breaks down or mechanical damage As a rule, repairs are not required, only the LCD panel is replaced; only in some cases does it make sense to repair it.

As we can see, on the back of the LCD display there are many connectors and a printed circuit board for controlling the monitor backlight, which is hidden behind a metal strip. The main element of the board is the image-forming chip; a cable comes off the board, which can also cause the monitor to break down.

Monitor Interface Board

In service manuals it is usually designated main board; in the photo above it is on the right with connectors for connecting to a computer. The board itself contains two eight-bit microcontrollers. The first of these is the Control Processor, which is connected via the I2C bus to the 24LCxx series memory. The second microprocessor is a monitor scaler; it is designed to process an analog video signal and transmit it in digital form to an LCD panel. It also performs secondary tasks related to video image scaling, creating a display menu, processing analog RSL signals and many other functions.

An indirect sign of a defective monitor scaler is the incorrect display of the image on the monitor screen, possible artifacts and stripes on it. Sometimes the problem disappears after soldering the microcontroller pins, and sometimes after some time the problem appears again and then it is necessary to replace the board or a very difficult operation to resolder the microcontroller.

Monitor power supply. Repair and Troubleshooting

The element that most frequently fails and, accordingly, most often requires repair is the pulsed one.

The power supply of a modern monitor with an LCD matrix consists of two parts. The first is an AC/DC adapter and the second is a DC/AC inverter. The AC/DC adapter is designed to convert alternating mains voltage into a small DC voltage, usually about 12 volts, but not at all necessary

The DC/AC inverter is also designed to convert DC voltage into AC voltage, but with a different order of magnitude, about 600 - 700 V and a frequency of 50 kHz. High voltage is supplied to the electrodes fluorescent lamps, located in the matrix.

Most switching power supplies today consist of special chips and controllers.

For example, this monitor power supply uses the TOP245Y chip.

In the documentation for the TOP245Y chip you can find typical examples circuit diagrams power supplies. This can be used when repairing power supplies for LCD monitors, since the circuits largely correspond to the standard ones indicated in the description of the microcircuit.

The TOP245Y microcircuit is a complete functional device that contains a PWM controller and a powerful field-effect transistor, switching with a high frequency reaching hundreds of kilohertz.

When repairing and eliminating defects, first of all you need to pay attention to oxide capacitors and preferably them. In addition, the rectifier very often fails, which can also be easily checked with a conventional multimeter in continuity mode in accordance with the diagram.

Monitor inverter and its repair

The inverter performs the following functions in the monitor:

converts direct voltage into high-voltage alternating voltage;
stabilizes the backlight lamp current;
adjusts brightness;
matches the output stage of the inverter circuit with the input resistance of the backlight lamp;
provides protection against short circuit and overload

The principle of constructing an inverter for a modern monitor is shown in structural diagram Below, this diagram is suitable for all inverters, which simplifies the process of repairing them

The sleep mode and inverter activation block is built on keys Q1, Q2. which switch the monitor to operating mode after 2…3 s. The switch-on voltage is supplied from the interface board and the inverter is switched to operating mode. The same keys turn off the inverter when the monitor switches to any power saving mode.

The unit for monitoring and controlling the brightness of the backlight and PWM lamps receives the brightness regulator voltage from the interface (main board) of the monitor board, after which it is compared with the OS voltage, and then a signal is generated that controls the PWM pulse repetition rate.

These pulses are needed to control the DC/DC converter (1) and synchronize the operation of the converter-inverter. The amplitude of the pulses is constant and depends only on the supply voltage, but their frequency varies depending on the brightness voltage and the threshold voltage level. The DC voltage from the DC/DC converter is supplied to the autogenerator.

The autogenerator is turned on and controlled by PWM pulses.

The protection unit (5 and 6) monitors the voltage and current at the output of the inverter unit and generates voltages feedback(OS) and overload. If the value of one of these voltages, for example in the case of a short circuit, overload or low supply voltage level, is above the threshold value, the autogenerator is turned off.

All main components of the inverter unit are made in SMD design.

Typical faults of LCD monitors

Starting to inspect the power supply board, we replace all the found burnt parts and swollen capacitors. It is also advisable to inspect the board and soldering under a microscope for possible microcracks. If the monitor is more than 2 years old, then by 50% there will be microcracks in the soldering. Believe it or not, the cheaper the monitor, the worse its assembly, and even the special failure to wash out the active flux.

The image blinks when the monitor is turned on. Most likely the problem is hidden in the power supply. Of course, you first need to check the cables and their secure connection with the connectors, but if this does not help, then the blinking image tells us that the monitor backlight is constantly jumping off. desired mode. Most often, the reason is hidden in swollen electrolytic capacitors, microcracks in soldering, or a faulty TL431 microassembly.

LCD monitor turns off spontaneously or does not turn on immediately. The reason is similar - swollen capacitors, microcracks, faulty TL431. With this problem, you can also hear a nasty high-frequency squeak from the backlight transformer.

No monitor backlight, (the image can be seen under bright external light). The power supply and inverter boards are burnt out, or the backlight lamps are faulty. If you have a monitor with LED backlight LED, then there is a darkening of the image in places at the edges of the display. It is better to start repairs by checking the power supply and inverter board.

Vertical stripes on the monitor screen. This is a very unpleasant malfunction, because the matrix (screen) has become 99% unusable due to broken contact between the signal cable and the LCD display, and finding a new cable is very problematic

There is no image, but the backlight works. That is, we see plain white, gray or blue screen. First you need to check the cables and try connecting the monitor to another system unit or video card. Also check whether it is possible to display the monitor menu on the screen. If nothing has changed, we begin to check the power supply board. Or rather, the presence of voltages with nominal values ​​of 5, 3.3 and 2.5 Volts. If they are present and correspond to the nominal value, then carefully inspect the board of the video signal processing unit. This module contains a microcontroller; you need to check whether power is supplied to it. If everything is normal, then we check all the monitor cables. Their contacts should not have any traces of carbon deposits or darkening. If you find something, wipe it off with alcohol. You should also check the cable and the board with control buttons. If none of the above helped, then the firmware may have failed or the microcontroller may have failed. This often happens from voltage surges in the 220 V network or from the natural aging of radio components.

The monitor does not respond to pressing control buttons. Remove the frame or back cover and take out the board with the buttons. Most often we see a crack in the board or in the solder. Sometimes there are faulty buttons or the cable itself. If you find a crack in the board, the area needs to be cleaned and soldered well.

Low monitor brightness. This happens due to aging of the backlight bulbs. In addition, it is likely that the inverter parameters will decrease. It is treated by replacing the backlight lamps and very rarely by repairing the inverter.

Noise, moire and jittery image on the monitor. Very often this happens due to bad interface cable. If the replacement does not help, then there is probably some kind of power interference getting into the imaging circuit. You can get rid of them by installing additional filter tanks for power supply on the signal board.

Goal of the work: Learn how to repair a monitor, what parts need to be replaced if the monitor breaks down

Theoretical information:

Distortion of the image on the top of the screen: lines are “knocked out”, shifted within a small range

The problem appears only at a frame rate of 100 Hz at a resolution of 1024 x 768, or at a frequency of 120 Hz at a resolution of 800 x 600.

Replacing diodes and capacitors (1 µF x 50 V) in the gate circuit of field-effect transistors for S-raster correction did not give any result. Using an oscilloscope, monitoring the S-correction signals coming from the microcontroller and the switches on field effect transistors(opening-closing) showed that all elements are operational.

The reason turned out to be increased ripple voltage of 13 V, which is generated by the power supply for the driver personnel scan. This was caused due to the "loss" of capacitance of the filter electrolytic capacitor in this circuit.

Progress:

LG FB770G-EA (CA-113 chassis)

When turned on, the monitor works, but when it is switched to standby mode (turning on the energy saving mode), it does not switch back to working mode (when a video signal appears)

At the same time, the green LED on the front panel blinks, the power supply is working, and there is a low potential at the DPMF & DPMS microcontroller pins.

Replacing the synchroprocessor (TDA 4841), reset chip (KIA 7042), 12 MHz resonator and EEPROM (2408) did not give any result. Replacing the microcontroller solved this problem.

LG T717BKM ALRUEE" (CA-136 chassis)

There is no line synchronization (see Fig. 1). Synchronization is only available in 1024 x 768 (85 Hz) mode, and a black horizontal bar 0.5 cm wide appears at the top of the screen. When the signal cable is disconnected, there is also no synchronization. Replacing the microcontroller, EEPROM chip, and filter capacitor along the B+ circuit did not give any results. After replacing capacitors C604, C605, C602 (external circuits of the synchroprocessor), synchronization was restored.

Samsung SyncMaster 797DF" (chassis LE 17ISBB/EDC)

The device does not turn on

Control of the power supply showed that the rectified mains voltage is supplied to controller IC601, but there are no secondary voltages at its outputs. After replacing the IC601 chip, the monitor's functionality was restored.

Quite often, in monitors of this type, the rectifying diode in the secondary circuit of the 14 V power supply fails. As a result, the IP controller switches to protection mode and there are no secondary voltages at the output of the unit.

LG Flatron T710BHK-ALRUE

When you turn on the monitor, the power supply protection is triggered

All output voltages are greatly underestimated (within 2...4 V), and the voltage at the output of the 50 V channel is 10...20 V. The transistor of the PWM controller B+ Q719 gets very hot.

Along with it, the filter capacitor C744 (47 µF x 160 V) also heats up. Checking the elements of this unit revealed a faulty diode D710 (UF 4004) - a short circuit. After replacing it, the monitor works fine.

Abnormal horizontal image size

The problem was solved by replacing the LM358 chip (installed in the horizontal size correction circuit).

Samsung 959NF" (chassis AQ19NS)

20-30 minutes after turning on the monitor, a line shift is observed in the image, not over the entire raster and with different shift values

Checking the filter capacitor in the mains rectifier and the scan synchronization circuit with the power source showed that everything is normal. The filter capacitor C650 (100 µF x 16 V), installed at the output of the 5 VIC650 voltage regulator, turned out to be faulty.

A similar defect often appears in Samsung models SyncMaster 757nf (chassis AQ17NSBU/EDC).

Samtron 56E (chassis PN15VT7L/EDC)

When turned on, a high appears for a second and protection is triggered

Control of the elements of the secondary rectifiers, TDKS showed that everything is normal.

If you disconnect the 50 V voltage circuit from the horizontal scan, the protection does not work.

After replacing the filter capacitor C407 (150uF x 63V), the monitor started working.

Samsung Syncmaster 750p

The image is unclear, doubles, and the defect appears even on the on-screen menu image and when the video source is turned off. When connected to the computer for some time (about 5 minutes), the image is normal, then a glitch begins: first, the image begins to “twitch” along the lines, then the lines move horizontally relative to each other and the “twitching” stops.

The reason turned out to be the voltage filter capacitor B+ C402 (10 µF x 250V). It is installed at the output of the DC/DC step-down converter on transistor Q403.

The monitor does not work, the LED on the front panel is blinking (green color)

Monitoring of the secondary circuits showed the presence of a short circuit in the horizontal power supply circuit. The PWM controller transistor B+ Q719 (breakdown) and the filter capacitor C740 (leakage) turned out to be faulty.

LG T730PHKM (CA-139 chassis)

When you turn on the monitor, the LED on the front panel lights up and goes out after 2-3 seconds. Horizontal scanning does not start at this time (no high voltage). All power supply voltages are normal, replacing the microcontroller and flashing the EEPROM did not produce any results

Monitoring the signals at the microcontroller pins showed that there is a low potential at one of the inputs connecting the K1 keyboard, although no button is pressed (there should be a potential of 5 V). The reason turned out to be a factory defect: the head of the screw fixing the keyboard board shorted the K1 bus to ground. After installing the dielectric washer, the monitor started working

Samsung SyncMaster 757NF

No image. All secondary voltages of the power supply are normal, except for 6.3 V. The output of this channel is only 3.8 V, and if you disconnect the kinescope board, the voltage returns to normal - 6.4 V

The reason is a defective capacitor C642 (1000 µF x 16 V) - loss of capacitance. After replacing it, the image appeared.

Compag p110, Sony gdm-5OOps

The monitor does not turn on, the indicator on the front panel is blinking

The safety resistor R617 (0.47 Ohm) in the 200 V voltage circuit turned out to be broken. After replacing it, the monitor started working, but the horizontal raster size was reduced. In addition, a distortion of the vertical raster (S-shaped) appeared. All secondary voltages of the power supply were normal, including 200 V.

Using the element-by-element test method, a faulty capacitor in the dynamic focusing unit C717 (22 µF x 100 V) was determined. After replacing it, the image became normal.

Samsung SyncMaster 750s (dp17ls chassis)

The image is "blurry". If you adjust the Screen and Focus potentiometers on the TDKS, then there is a normal reaction, the brightness and focus change independently. Supply voltage is normal. The EEPROM firmware didn't do anything.

Sometimes this happens if the wires through which the focusing voltages F1 and F2 are supplied to the kinescope board are mixed up during repairs, but not in this case. After replacing these wires, the image became a little clearer, but still abnormal. It turned out that wires F1 and F2 are not soldered to the kinescope panel, but are fixed using spring contacts. After disassembling and cleaning these contacts (there were traces of corrosion), the image returned to normal.

Horizontal size is not adjustable

The adjustment signal is supplied from the microcontroller to the base of transistor Q714, but is absent from the collector. Element-by-element check revealed faulty transistor Q707 in the S-correction circuit. The diode in the gate circuit of this transistor D707 also turned out to be faulty. After replacing these elements, the horizontal size began to be adjusted.

DIY monitor repair:

1. First stage: Opening the monitor and initial inspection of the internal components.

First of all, you need to disconnect all cables from the monitor. For some monitor models, the signal cable has a one-piece outer join with a monitor.

For most LCD monitors, the body consists of a front frame and a back cover, which often serves as the basis of the entire structure. It should be noted that there is no one recommendation for all designs and each manufacturer has its own characteristics that are unique to certain models.

Before starting the opening, you need to take care of a flat surface (for example, a table) and a soft material covering the flat surface and preventing the LCD matrix from scratching. It is also necessary to organize sufficient lighting for the workplace. In order to disassemble the monitor, you will need to separate the stand bracket from the body by unscrewing the mounting screws or self-tapping screws. You will need Phillips screwdrivers, types PH1, PH2, and for devices from some manufacturers, types in the form of a six-pointed star may be required. It is convenient to use a universal bit holder with a set of interchangeable bits of different sizes and types.

After unscrewing and removing the fastening threaded elements, it is advisable to remember which fastening element was screwed into which hole. The next step is to separate the front frame from the back cover. Particular attention should be paid to the fact that in many designs, the front frame is attached to the back cover using plastic latches. We do not recommend using a slotted screwdriver, kitchen knife or other unsuitable objects at this stage to avoid deformation of the case, the appearance of burrs and chips. We do not recommend using excessive force if the front frame cannot be separated. Careless movement and excessive, misdirected forces can lead to irreparable damage to the latches, which in turn will lead to the appearance of unnatural gaps and changes appearance Your device.

After separating the front frame, it is necessary to disconnect the connectors of the high-voltage wires on the inverter board going to the LCD panel. We do not recommend pulling the wires to avoid breaking the conductors, but removing the connectors of high-voltage wires with special tweezers.

There are four main components of an LCD monitor:

Power supply providing power to the signal processing unit, LCD module and high-voltage converters (inverters)

Assembly of high-voltage voltage converters (inverters) powering CCFL backlight lamps.

Signal processing unit. In multimedia monitors, the signal processing unit is much more complex and contains large quantity elements.

LCD module. The design of the LCD module is described in the article “How the LCD monitor module works”

Before starting to search for the cause of the malfunction, you should carry out an initial inspection of the components to identify elements with a changed shape, as well as darkening on the boards, indicating heating of the components. Heating of a component until the board material underneath darkens may indicate a faulty component or a fault in the circuit to which the component belongs.

2. Second stage: Determining the cause of the malfunction

To determine the cause of the malfunction, you will need a device diagram (or service manual), a multimeter with continuity functions, DC voltage measurement and alternating current, measuring the capacitance of capacitors, as well as an oscilloscope (to diagnose the signal processing unit, a digital oscilloscope with memory may be required)

3. Third stage: Replacement of faulty components

To replace faulty components, you may need a soldering station with tip temperature control, and to replace elements of the signal processing unit, a special hot-air soldering station. Note that some microcircuits are sensitive to excessive heat and may fail if overheated. Also, pads and tracks should not be allowed to overheat, since excessive heating may cause delamination and breakage of the conductor on the printed circuit board. If microcircuits in BGA and FBGA packages malfunction, you may need infrared soldering equipment with an appropriate set of stencils, as well as a special flux.

4. Fourth stage: Post-repair testing

After replacing faulty components, post-repair testing is a necessary mandatory step. At the testing stage you will need an electronic thermometer, voltmeter direct current, ammeter and test signal source. The minimum testing time for a restored monitor, according to practical statistics, is at least 12 hours. In cases of troubleshooting that appear during warm-up or are unsystematic in nature, the testing time should be increased to 20-30 hours. Testing must take place under the constant supervision of a specialist.

5. Fifth stage: Assembling the monitor

Assembling the monitor should occur in the reverse order of opening. Particular attention should be paid to the screwing force and the length of the screws and screws being screwed in. If the screw or self-tapping screw is longer, there is a risk of damage to the housing elements and the LCD panel.

In one article it is impossible to describe all possible design features and methods for restoring monitors, and in each specific case the path to finding the cause of the malfunction is unique. Sometimes an engineer with many years of practical experience has to strain his head to understand the design and circuit design.

Conclusion: During practical work I studied theoretical material, learned how to repair a monitor and learned what parts need to be replaced when a monitor breaks down, and how to repair a monitor with your own hands.

There are disappointments in life, as they say. I came home, turned on the computer, then bam... the monitor doesn’t turn on... what the... and this way and that, no, it’s still completely dead, it doesn’t light up and that’s it, even if you crack it. The system unit is working, but the monitor is not, it’s strange... well, you’ll have to pick at your monitor. You can, of course, buy a new one, but if you have a head on your shoulders and time, then you can see for yourself what’s wrong with it, at least for fun.

Here is a breakdown and repair option for an old LG FlatronL1953S LCD monitor. Over time, when your monitor is 6 - 7 years old, a lot of dust gets clogged in it or capacitors often fly off.

This monitor looks like this:

Unwind:

Four screws have been removed. Now you need to remove the back cover. Back cover It is not secured with screws, it is secured together with the front frame with latches.

You need to separate the latches very carefully, as they are quite fragile and can be easily broken. And there are enough of these latches all over the monitor. You need to use all kinds of available items and methods. Something thin so that there is something to pick up.

Hooray! Somehow they opened the lid :)

So, let's see what's available here. The protective casing is made of metal, it covers the boards and is secured with tape. Yes... that's how it is... Koreans are somewhat similar to us in this regard, everything is on tape, wire and electrical tape, thrifty guys :) But at least one thing is good that there are no more these nasty latches.

Hmmm... The guts of this monitor are not rich in variety; they consist of a couple of boards: a power supply board and a control board. That's all.

Let's start with nutrition. We take out the power supply board. Most likely there will be a whole bunch of dust on it. Most people don't clean it from the time they buy it until the end of its life. Of course, all dust must be removed, since it can also harm the operation of your monitor.

Power supply board

Examine the board very carefully. Check the fuses first. There is only one installed on this board. Here he is in good order, everything is fine with him. Let's look further...

Here it is! Do you see? These capacitors look suspicious, they are swollen, let’s take a closer look at them...

Well, everything is clear, the most probable cause dead monitor - these are electrolytes. Below are analogues that can be replaced if there are no similar factory ones that were originally installed.

Which were installed and indicated with a hyphen what they were changed to:

• 1000 uF 25V - 1000 uF 25V made in the USSR
• 1000 µF 25V - 1000 µF 25V
• 470 µF 16V - 470 µF 25V
• 680 µF 16V - 470 µF 25V

All this was taken from the trash that was lying around the house, the ones closest in characteristics were selected and this is what came out:

It is not known whether this large aluminum cap of the capacitor is connected or not to the positive or negative contact, for this reason it is simply insulated with a piece of electrical tape, you can ring it just in case.

The final board looks like this:

We put everything back together, turned it on... and it worked! Great. You see, it turned out that the death of the monitor was clinical, but not complete :) And you can continue to use it.

All the best.