DIY computer monitor repair

In detail: do-it-yourself computer monitor repair from a real master for the site my.housecope.com.

Today I want to share with you the experience of repairing a monitor with my own hands. I repaired my old one LG Flatron 1730s... Like this:

This is a 17 "LCD monitor. I must say right away that when there is no image on the monitor, we (at work) immediately refer such copies to our electronics engineer and he deals with them, but there was an opportunity to practice 🙂

To begin with, let's understand the terminology a little: earlier, CRT monitors (CRT - Cathode Ray Tube) were in use. As the name implies, they are based on a cathode ray tube, but this is a literal translation, it is technically correct to talk about a cathode ray tube (CRT).

Here is a disassembled sample of such a "dinosaur":

Nowadays LCD type of monitors (Liquid Crystal Display - display on the basis of liquid crystals) or simply LCD is in vogue. These designs are often referred to as TFT monitors.

Although, again, if we speak correctly, then it should be like this: LCD TFT (Thin Film Transistor - screens based on thin-film transistors). TFT is simply the most widespread variety, more precisely, LCD (liquid crystal) display technology.

So, before we start repairing the monitor ourselves, let's consider what “symptoms” did our “patient” have? In short: there is no image on the screen... But if you look a little more closely, then various interesting details began to emerge! 🙂 When turned on, the monitor showed an image for a split second, which immediately disappeared. At the same time (judging by the sounds), the system unit of the computer itself worked properly and the operating system was loaded successfully.

Video (click to play).

After waiting for a while (sometimes 10-15 minutes), I found that the image appeared spontaneously. Repeating the experiment several times, I was convinced of this. Sometimes for this, however, it was necessary to turn off and turn on the monitor with the "power" button on the front panel. After resuming the picture, everything worked without interruptions until the computer was turned off. The next day, history and the whole procedure were repeated again.

Moreover, I noticed an interesting feature: when the room was warm enough (the season is no longer summer) and the batteries were heated fairly, the idle time of the monitor without an image was reduced by five minutes. There was a feeling that it warms up, reaching the desired temperature regime and then works without problems.

This became especially noticeable after one day the parents (the monitor was with them) turned off the heating and the room became quite fresh. In such conditions, the image on the monitor was absent for about 20-25 minutes, and only then, when it got hot enough, did it appear.

According to my observations, the monitor behaved exactly like a computer with certain problems of the motherboard (capacitors that have lost capacity). If it is enough to warm up such a board (let it run or direct a heater towards it), it normally “starts up” and, quite often, works without interruptions until the computer is turned off. Naturally, this is - until a certain moment!

But at the early stage of diagnosis (before opening the patient's case), it is highly desirable for us to make the most complete picture of what is happening. According to it, we can roughly navigate in which node or element is the problem? In my case, after analyzing all of the above, I thought about the capacitors located in the power supply circuit of my monitor: we turn on - there is no image, the capacitors are warming up - it appears.

Well, it's time to test this assumption!

Let's disassemble! First, using a screwdriver, unscrew the screw that secures the bottom of the stand:

Then, - remove the corresponding screws and remove the base of the stand attachment:

Next, using a flat-tipped screwdriver, we pry the front panel of our monitor and in the direction indicated by the arrow, we begin to carefully separate it.

Slowly, we move along the perimeter of the entire matrix, gradually removing the plastic latches holding the front panel from their seats with a screwdriver.

After we disassembled the monitor (separated its front and rear parts), we see the following picture:

If the “insides” of the monitor are attached to the back panel with adhesive tape, peel it off and remove the matrix itself with the power supply and control board.

The back plastic panel remains on the table.

Everything else in the disassembled monitor looks like this:

This is how the “filling” looks in the palm of my hand:

Let's show a close-up of the panel of settings buttons that are displayed for the user.

Now, we need to disconnect the contacts connecting the cathode backlight lamps located in the monitor matrix with the inverter circuit responsible for their ignition. To do this, we remove the aluminum protective cover and see the connectors under it:

We do the same on the opposite side of the monitor's protective casing:

Disconnect the connectors from the monitor inverter to the lamps. Who cares, the cathode lamps themselves look like this:

They are covered on one side with a metal casing and are located in it in pairs. The inverter “lights up” the lamps and adjusts the intensity of their light (controls the brightness of the screen). Now, instead of lamps, LED backlights are increasingly used.

Advice: if you find that on the monitor suddenly the image is gone, take a closer look (if necessary, illuminate the screen with a flashlight). Perhaps you will notice a faint (faint) image? There are two options here: either one of the backlight lamps is out of order (in this case, the inverter simply goes “in defense” and does not supply power to them), remaining fully operational. The second option: we are dealing with a breakdown of the inverter circuit itself, which can either be repaired or replaced (in laptops, as a rule, they resort to the second option).

By the way, the laptop inverter is located, as a rule, under the front outer frame of the screen matrix (in the middle and bottom of it).

But we got distracted, we continue to repair the monitor (more precisely, for now, chick it) 🙂 So, having removed all the connecting cables and elements, we disassemble the monitor further. We open it like a shell.

Inside we see another cable connecting, protected by another casing, the matrix and monitor backlight lamps with the control board. Peel off the scotch tape up to half and see under it a flat connector with a data cable in it. We carefully remove it.

We put the matrix separately (we will not be interested in it in this repair).

This is how it looks from the back:

Taking this opportunity, I want to show you the disassembled monitor matrix (recently they tried to repair it at work). But after analysis, it became clear that it would not be possible to fix it: some of the liquid crystals on the matrix itself burned out.

In any case, I shouldn't have seen my fingers behind the surface so clearly! 🙂

The die is secured in a frame that holds and holds all of its parts together using snug plastic snaps. In order to open them, you will have to work thoroughly with a flat screwdriver.

But with the type of do-it-yourself monitor repair that we are doing now, we will be interested in another part of the design: the control board with the processor, and even more so, the power supply of our monitor. Both of them are shown in the photo below: (photo - clickable)

So, in the photo above, on the left, we have the processor board, and on the right, the power board combined with the inverter circuit. A processor board is often referred to as a scaler board (or circuit).

The scaler circuit processes the signals coming from the PC. In fact, a scaler is a multifunctional microcircuit, which includes:

microprocessor
a receiver (receiver) that receives a signal and converts it into the desired form of data, transmitted via digital interfaces for connecting a PC
an analog-to-digital converter (ADC) that converts the input analog R / G / B signals and controls the resolution of the monitor

Read also: Abac compressor DIY repair

In fact, a scaler is a microprocessor optimized for the task of image processing.

If the monitor has a frame buffer (random access memory), then work with it is also carried out through the scaler. For this, many scalers have an interface for working with dynamic memory.

But we - again distracted from the repair! Let's continue! 🙂 Let's take a close look at the monitor power combo board. We will see such an interesting picture there:

As we assumed at the very beginning, remember? We see three swollen capacitors requiring replacement. How to do it correctly is described here in this article of our site, we will not be distracted once again.

As you can see, one of the elements (capacitors) swelled not only from above, but also from below, and some of the electrolyte flowed out of it:

To replace and effectively repair the monitor, we will need to completely remove the power board from the casing. We unscrew the fastening screws, take out the power cable from the connector and take the board in our hands.

Here is a photo of her back:

I want to say right away that quite often the power board is combined with the inverter circuit on one PCB (printed circuit board). In this case, we can talk about a combination board, represented by the power supply of the monitor (Power Supply) and the inverter of the backlight (Back Light Inverter).

In my case, this is exactly the case! We see that in the photo above, the lower part of the board (separated by a red line) is, in fact, the inverter circuit of our monitor. It happens that the inverter is represented by a separate PCB, then there are three separate boards in the monitor.

The power supply (the upper part of our PCB) is based on the FAN7601 PWM controller microcircuit and the SSS7N60B field-effect transistor, and the inverter (its lower part) is based on the OZL68GN microcircuit and two FDS8958A transistor assemblies.

Now we can safely start repairing (replacing capacitors). We can do this by conveniently placing the structure on the table.

This is how the area of interest to us will look after removing faulty elements from it.

Let's take a close look at what nominal capacitance and voltage do we need to replace the elements soldered from the board?

We see that this is an element with a rating of 680 microfarads (mF) and a maximum voltage of 25 volts (V). In more detail about these concepts, as well as about such an important thing as maintaining the correct polarity when soldering, we talked with you in this article. So, let's not dwell on this again.

Let's just say that we have failed two 680 mF capacitors with a voltage of 25V and one at 400 mF / 25V. Since our elements are connected in parallel to the electrical circuit, we can safely use two 1000 mF capacitors instead of three capacitors with a total capacity (680 + 680 + 440 = 1800 microfarads), which will add up to the same (even greater) capacitance.

The capacitors removed from our monitor board look like this:

We continue to repair the monitor with our own hands, and now it is time to solder the new capacitors in place of the removed ones.

Since the elements are really new, they have long “legs”. After soldering in place, just carefully cut off their excess with side cutters.

As a result, we got it like this (for the sake of order, for two 1000 microfarad capacitors, I put an additional 330 mF element on the board).

Now, we carefully and carefully reassemble the monitor: fasten all the screws, connect all cables and connectors in the same way, and, as a result, we can proceed with an intermediate test run of our half-assembled structure!

Advice: there is no point in putting the entire monitor back together, because if something goes wrong, we will have to disassemble everything from the very beginning.

As you can see, the frame, signaling the absence of a connected data cable, appeared immediately.This, in this case, is a sure sign that the repair of the monitor with our own hands was successful with us! 🙂 Previously, until the malfunction was corrected, there was no image at all until it warmed up.

Mentally shaking hands with ourselves, we assemble the monitor to its original state and (for testing) we connect it with a second display to the laptop. We turn on the laptop and see that the image immediately "went" to both sources.

Q.E.D! We just repaired our monitor ourselves!

note: To find out what other types of TFT monitor malfunctions there are, follow this link.

That's all for today. I hope this article was helpful to you? See you next on the pages of our site 🙂

Objective: Learn to repair the monitor, what parts need to be replaced if the monitor breaks down

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

The malfunction appears only at a vertical frequency of 100 Hz at a resolution of 1024 x 768, or at a frequency of 120 Hz at a resolution of 800 x 600.

Replacement of diodes and capacitors (1 μF x 50 V) in the gate circuit of the field-effect transistors S-correction of the raster did not give any result. Oscilloscope control of S-correction signals coming from the microcontroller and switches on field-effect transistors (open-close) showed that all elements are operational.

The reason turned out to be in the increased voltage ripple of 13 V, which is formed by the power supply for the vertical scan driver. This was due to the “loss” of the capacity of the filtering electrolytic capacitor in this circuit.

When turned on, the monitor works, but when you switch it to standby mode (turn on the power 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 is blinking, the power supply is working, the potential of the DPMF & DPMS microcontroller is low.

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 ”(chassis CA-136)

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

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

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

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

Power supply protection activates when monitor is turned on

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 PWM transistor of the B + Q719 controller is very hot.

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

Horizontal image size is abnormal

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

Samsung 959NF ”(chassis AQ19NS)

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

Checking the filter capacitor in the mains rectifier, the sweep synchronization circuit with the power supply showed that everything is normal. The filtering capacitor C650 (100 μF x 16 V) installed at the output of the 5 V IC650 voltage regulator turned out to be faulty.

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

Samtron 56E (chassis PN15VT7L / EDC)

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

Monitoring of secondary rectifier elements, 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.

The image is indistinct, doubles, and the defect appears even in the image of the on-screen menu and when the video signal source is turned off. When connected to a computer, the image is normal for some time (about 5 minutes), then a crash starts: at first, the image starts to "twitch" along the lines, then the lines are shifted horizontally relative to each other and the "jerking" stops.

The reason turned out to be in the filtering capacitor of voltage B + C402 (10 μF x 250V). It is installed at the output of a DC / DC buck converter using a Q403 transistor.

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

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

When the monitor is turned on, the LED on the front panel lights up and turns off after 2-3 seconds. The horizontal scan does not start at this time (there is no high voltage). All voltages of the power supply are normal, replacing the microcontroller and flashing the EEPROM did not give any result

Monitoring the signals at the microcontroller pins showed that there is a low potential at one of the inputs for connecting the K1 keyboard, although not a single button is pressed (there should be a potential of 5 V). The reason was a factory defect: the head of the self-tapping screw fixing the keyboard board shorted the K1 bus to ground. After installing the dielectric washer, the monitor started working

There is no picture. All secondary voltages of the power supply are normal, except for 6.3 V. At the output of this channel, there is only 3.8 V, and if you turn off the kinescope board, the voltage returns to normal - 6.4 V

The reason for the defective capacitor C642 (1000 μF x 16 V) is the 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 open. After replacing it, the monitor started working, but the horizontal raster size was reduced. In addition, there is a vertical raster distortion (S-shaped). All secondary voltages of the PSU were normal, including 200 V.

A faulty capacitor in the C717 dynamic focusing unit (22 μF x 100 V) was identified by the method of element-by-element verification. 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, that is, a normal reaction, the brightness and focus change independently. The supply voltage is normal. EEPROM firmware failed

Sometimes this happens if you confuse the wires during the repair, through which the focusing voltages F1 and F2 are supplied to the CRT board, but not for this case. After replacing these wires, the image became a little clearer, but still abnormal. It turned out that the wires F1 and F2 are not soldered to the CRT panel, but are fixed with 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 fed from the microcontroller to the base of the Q714 transistor, but is absent from the collector. Element check has identified a faulty transistor Q707 in the S-correction circuit. The diode in the gate circuit of this D707 transistor also turned out to be faulty. After replacing these elements, the horizontal size began to be adjusted.

DIY monitor repair:

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

First of all, you must disconnect all cables from the monitor. For some monitor models, the signal cable has a permanent external connection to the monitor.

Most LCD monitors have a case with a front frame and a back cover, which often serves as the base of the entire structure. It should be noted that there is no one recommendation for all designs and each manufacturer has its own characteristics inherent only in certain models.

Before opening, you need to take care of a flat surface (for example, a table) and a soft material covering the flat surface and preventing scratches of the LCD matrix. It is also necessary to provide sufficient illumination of the workplace. In order to disassemble the monitor, you will need to separate the stand bracket from the case by unscrewing the mounting screws or self-tapping screws. You will need Phillips screwdrivers such as PH1, PH2, and for some manufacturers' devices, you may need six-star type. It is convenient to use a universal bit holder with a set of replaceable bits of different sizes and types.

After unscrewing and removing the threaded fasteners, it is advisable to remember which fastener was screwed into which hole. The next step is to separate the bezel from the back cover. It should be paid special attention that in many designs - the front frame is attached to the back cover by means of plastic latches. We do not recommend using a slotted screwdriver, a kitchen knife and other unsuitable objects at this stage in order to avoid deformation of the case, the appearance of scoring and chips. We do not recommend using excessive force if the front frame “does not give in” to separation. Careless movement and excessive, incorrectly directed forces can lead to irreparable breakage of the latches, which in turn will lead to unnatural clearances and a change in the appearance of your device.

After removing 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 in order to avoid breaking the conductors, but to remove the connectors of the high-voltage wires with special tweezers.

There are four main components of an LCD monitor:

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

Node of high-voltage voltage converters (inverters) of CCFL power supply of backlight lamps.

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

LCD module. The structure of the LCD module is described in the article "How the LCD monitor module works"

Before starting the search for the cause of the malfunction, an initial inspection of the nodes should be performed to determine the elements with a changed shape, as well as darkening on the boards, indicating heating of the components. If a component heats up until the board material underneath darkens, this could indicate a component failure or a malfunction in the circuit to which that component belongs.

2. Stage two: Determining the cause of the malfunction

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

3. Stage three: Replacing defective components

To replace faulty components, you may need a soldering station with temperature control of the tip, 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, overheating of the pads and tracks should not be allowed, since with excessive heating, delamination and breakage of the conductor on the printed circuit board may occur.If the microcircuits in BGA and FBGA packages are malfunctioning, 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 defective components, a necessary mandatory step is testing after repair. The testing phase will require an electronic thermometer, a DC voltmeter, an ammeter, and a test signal source. The minimum testing time for a restored monitor, according to statistics from practice, is not less than 12 hours. In cases of elimination of malfunctions that appear with warming up or are of an unsystematic nature, the testing time should be increased to 20-30 hours. Testing should take place under the constant supervision of a specialist.

5. Fifth stage: Assembling the monitor

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

Within the framework of one article, it is impossible to describe all the possible design features and methods of restoring monitors, and in each 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 circuitry solution.

Conclusion: In the course of practical work, I studied theoretical material, learned how to repair a monitor and learned what parts need to be replaced in case of a monitor breakdown, how to repair a monitor with my own hands.

It so happened that once the screen of the Samsung 740N monitor, which has faithfully served me for almost 11 years, suddenly went out almost immediately after turning it on. Other attempts to enable and disable were unsuccessful, because according to the signals from the sound card, the operating system was booted successfully, it became clear that the problem lies in the monitor. Of course, a radio amateur cannot so easily throw out an old electronic device without trying to fix it, well, or raskurochit broken device for parts, then how it goes.

A quick search [1-6] showed that the most common problem with this type of monitors is the failure of electrolytic capacitors in the power supply. In general, even the most novice radio amateur can do such repairs, so you can get by with the purchase of several radio components at the place of purchase of the monitor, which is a couple of orders of magnitude cheaper, the cost of your own time, of course, is not taken into account. But in order to repair something, you first need to get inside the monitor, do it carefully, without marks on the case, perhaps the most difficult part of the repair. First, you need to put the monitor face down, so that the surface of the screen would not be damaged, after that you should unscrew the screws holding the stand.

The back cover of the monitor is held by latches located around the perimeter of the monitor case. To open the latches, insert a strong thin object, such as an unnecessary plastic card or a metal ruler, into the gap between the screen frame and the back cover, and then sequentially and slowly unscrew all the latches holding the cover. Under the back cover, such a spectacle appears before us. In the next photo, the cover that covers the power connectors of the backlight lamps is also removed.

It should be noted that the metal casing visible in the photo above, to which most of the structural elements are attached, is fixed in the desired position with the help of the back cover and is not fixed to anything else. Before further disassembling the monitor, carefully document the wiring of all internal connectors. True, a real chance to confuse the connectors exists only for the power connectors for the backlight lamps.

Just in case, we fix the position of the remaining connectors.

Now, from the actual screen, you can remove the casing with the printed circuit boards fixed in it.

Then we remove the power supply board.

As expected, three failed electrolytic capacitors are visible on the board.

Finally, we disconnect the power supply board and remove the protective film that covers the board from the side of the printed conductors, this film is held on 3 plastic clips.

In addition to the obviously failed capacitors, a number of sources reviewed recommend replacing the capacitor C107 for preventive purposes.

This radio part has been replaced with a 47 μF x 250 V capacitor.

Just as the reviewed sources indicated, the fuse F301 breaks down along with the capacitors. In the photo, this is a green radio component, which is visible next to the swollen electrolytic capacitors.

We remove suspicious and clearly damaged radio components from the board. The main culprits are that the author of these lines was left without a computer on May 9, 2017.

In place of the failed radio components, we install similar capacitors. Instead of a 3 A fuse, a 3.15 A fuse with solder leads is installed.

After assembly, the monitor's performance was fully restored, after three weeks of intensive use, no deviations were noticed in the work. The author of the material is Denev.

What to do if the monitor stops turning on, watch a master class with step-by-step photos, how you can repair it yourself.

It often happens that, having worked faithfully for several years, the monitor suddenly refuses to turn on in one moment, although its green LED indicator continues to blink.

One of the possible reasons for this phenomenon, which even a novice radio amateur can cope with, will be revealed in this master class.

Here we will describe the repair of the SAMSUNG SyncMaster 540N LCD monitor, although over the past few months with a similar malfunction, 5 monitors fell into my hands - SAMSUNG SyncMaster with diagonal dimensions of 15 and 17 inches, Acer - 17 inches.

Despite the differences in design and different manufacturers, the principle of operation of power supplies is common for all and some of their parts are interchangeable.

After removing the cords, we proceed to disassemble the monitor.

Use a curly screwdriver to unscrew the screws securing the stand and remove it.

The stand is removed, we take a fairly strong knife - a folding one with a durable and non-springing blade will do.

We turn the monitor upside down, insert the knife blade into the gap between the monitor case and the front cover - always from some angle, not from the middle.

Slowly pushing the body parts apart with a knife, we slowly move to the middle and then to the opposite corner; then we repeat this operation with the side edges of the monitor.

Carefully lift the case up, turn it over - and it completely separates from the front frame, on which all the electronics remain, enclosed in a metal screen.

Remove the locking plate secured with stamped latches.

We take out the connectors from one side.

... and on the other. Carefully tear off the tape holding the wire to the metal base.

Remove the metal base in which the monitor's power supply is located.

The larger block, covered with a translucent insulating plate and secured with three screws, is the power supply.

Unscrew the screws, take out the connector with wires and.

... remove the power supply unit. By clicking on the photo, we will see three swollen electrolytic capacitors (they are highlighted in red circles) - this is the reason for the current “incapacitated” state of the monitor.

In addition, these parts are located in the output, low-voltage part of the power supply unit as power filters, which means that the probability of failure of the main part of the power supply unit is very small.

We solder the faulty parts and look at the inscriptions on their cases.

So, the culprits of all our troubles are capacitors with a capacity of 330 and 820 uF with an operating voltage of 25 V and 1200 uF - for 10 V.

We select a similar replacement (it is possible with a slightly higher operating voltage - if the dimensions allow) and install it instead of the faulty ones.

Putting the edge of the circuit board in the special grooves in the guides, put it in place and fix it with screws.

Next, we assemble the monitor in the reverse order, remembering to check the wires more often - so as not to accidentally transfer them anywhere.

Reinstall the case - it is also the back cover of the monitor. If its removal was quite laborious, now a few clicks on the edges of the monitor with your hands - and the case is assembled almost instantly.

We fasten the stand - and we can assume that the repair of the computer monitor with our own hands is completed and we can start testing our device.

We connect the monitor with a cable to a computer or laptop, turn on the power - and enjoy the result of our own hands.

In the 21st century, we can no longer imagine our life without a personal computer. For us, he is both an assistant in work, and a device for recreation, and a means of communication. But when this "miracle" apparatus breaks down, we have the first and seemingly correct thought - to turn to a specialist. But you don't always need to rush to do it.

Try to fix the problem yourself first. In some cases, this is quite possible.

And in which ones, we will now figure out.

With this malfunction, first of all, you should check the power cable that connects to the system unit. You need to make sure that it fits snugly into the socket of the system unit and the outlet.

The integrity of the cable can be checked by replacing it with another one. For example, taking the wire from the monitor.

If these operations did not help. Open the side panel of the system unit and check if the voltage indicators on the motherboard are on. If there is no glow, then, most likely, the power supply is faulty. Replace it.

But if the replacement of the power supply did not help to eliminate the malfunction, then it's time to contact the master.

First, make sure the Power button is on. If not, then check the power cable by analogy with checking in the system unit.

If the "Power" button is lit, but the image does not appear on the screen, a possible malfunction may be a breakdown of the video card. It is very easy to make sure that the video card is faulty. It is necessary to disconnect the signal cable from the video card and connect it to the input of the integrated video card, which is usually built into the motherboard. If after this operation the image appears, replace the video card. Otherwise, contact a specialist.

The main reason for this is overheating of the processor or clogged registries. Overheating of the processor most often occurs due to the dusty elements of the motherboard. Therefore, it is necessary to open the side panel of the system unit and thoroughly clean all the elements from dust, especially the cooling fans.

Registries are cleaned using the CCleaner program of any version. Download, install the Russian-language version and follow the instructions to clean the registries.

Here are almost all the malfunctions that can be eliminated without the help of a specialist.

But it's never too late to learn and "heal" your computer on your own. Study it and it will save you a lot of time and money.

Now almost every home has a personal computer. Each user can make computer repairs himself, with his own hands.

The technique is quite reliable, especially in capable hands. Also, reliability, or better to say, the lifespan, will be added to it by a surge protector or UPS (uninterruptible power supply), because it is no secret to anyone that the voltage in the electrical network periodically jumps.

This phenomenon is associated with various factors, breakdowns in the network itself or a transformer box, the inclusion of three kettles, two hair dryers and a pair of heaters in one outlet, a strong wind plays with wires, well, and so on.And some elements of the computer are afraid not only of a jump in the network, but simply of the static electricity of the human skin. So, before we climb inside the computer, we will not grab our heads, but put our hands on the battery, after which we will take up the repair of the computer with our own hands, so to speak, closely.

So, the first problem - the computer does not turn on. The first thing we do, usually, we look to see if it is included in the network, after which we press the button ten times again. If it doesn't help, panic begins. You should not panic, check if there is electricity in the house. If so, there may be several faults. The most common problem is a faulty power supply.

By itself, it looks like a box with a fan inside. You can find out by connecting the computer with a different power supply. But few have one. You can also, after disconnecting the computer from the network, disconnect the power supply from the motherboard (wide connector, more often white, do not forget about the second smaller connector). When all the wires are disconnected, now we reconnect the computer to the network. On the wide connector of the power supply, we need to close two contacts: green and black (any black). If it does not start, we go to the store for a new one.

Wide power supply connector

Very rarely, the reason may lie in the breakdown of the power button. This is also easily verified. On the motherboard we find two pins where PWD SW is written next to them.

Power plugs on the motherboard

The easiest way to do this is to follow the wire from the button. We remove the button connection connector, and close them with a screwdriver. If it does not start, then it’s not her problem. Once again, this is an extremely rare occurrence and most likely the reason is in the power supply. After all, even a faulty motherboard will turn on, even for a second, but the cooling fans will work.

By the way, it is the cooling fans that are the main culprit for the huge amount of dust inside the computer case. Any electronics are afraid of dust. Especially difficult. So we periodically clean and blow out the computer. You can do this with a can of compressed air, a vacuum cleaner, a watercolor brush will help us a lot in this matter, I confess, I like the fox more.

The second problem is that it turns on and, immediately, turns off. I came across this several times in my practice. Either the motherboard or the processor is defective. Let's go in order. There are many voltage-rectifying capacitors on the motherboard. Due to overheating, they, over time, lose their capacity and fail. Therefore, make sure that the computer does not overheat. But don't rush to throw out the motherboard. The motherboard gradually fails from overheating. This is accompanied by the freezing of the computer, very often, with the same "Blue Screen of Death". So, the "mother" will not be covered right away, but will still shake your nerves for several months before that.

Processor and applying thermal paste to it

If it happened spontaneously.

Most likely, the processor is to blame, or rather, its insufficient cooling. And there is even a possibility that he is intact. What are we doing? Do not forget to put your hands on the battery. Disconnect the computer from the network. Remove the housing cover. We need to get to the processor. It is located under the largest heatsink, which, in turn, is located under the largest fan (in general, it is correct to call such a fan in a computer a "cooler") on the motherboard. You can see that there is a wire coming from the cooler, or rather three wires usually wound. Disconnect them. Now we are going to remove the cooler with the radiator. We are in no hurry to grab the screwdriver. On almost all modern motherboards, modern radiators are fastened with clips and removed / installed by hand.

You may have to tinker. Above all, do not apply force with your entire arm or body weight. Only gently and only with your fingers. Having removed this "construction", we see a small metal (on modern computers) box.The cover is opened by lifting the metal tab. We opened the lid and very carefully took out the processor. You will not see that it burned down, unless you throw it into the fire. First, look at the place where the processor was installed. There are many, many little paws. Look closely to see if one or more are bent. If it is bent, then holding your breath, you can try to straighten it with a needle, but I do not advise. We will postpone this procedure as a last resort. Next, we need thermal paste. You can purchase it at a computer store. Thermal paste helps transfer heat away from the processor to the heatsink. After all, if there is even the slightest angle between the planes of their surfaces, then there is also a gap. Thermal paste, as you might guess, eliminates this gap.