DIY CRT monitor repair

Until 2004-2005, CRT monitors and televisions, or, in other words, having a kinescope in their composition were distributed in mass use. They are also, like televisions, called monitors and CRT (cathode ray tube) type monitors. But progress does not stand still, and at one time LCD TVs were released, which included an LCD (liquid crystal) matrix. Such a matrix must be well illuminated by 4 CCFL lamps located on both sides, top and bottom.

This applies to 17 - 19 inch monitors and TVs. Larger TVs and monitors may have six or more lamps. Such lamps in appearance resemble ordinary fluorescent lamps, but, in contrast, are much smaller in size. Of the differences, such lamps will not have 4 contacts, as in fluorescent lamps, but only two, and their operation requires a high voltage - over a kilovolt.

Monitor backlight connector

So, after 5-7 years of operation, these lamps often become unusable, malfunctions are typical for ordinary fluorescent lamps. Here is some additional information. First, reddish tints appear in the image, a slow start, in order for the lamp to light up, it needs to blink several times. In severe cases, the lamp does not light up at all. The question may arise: well, one lamp has gone out, they are standing above and below the matrix, usually two pieces installed parallel to each other, let only three of them burn and the image will only be dimmer. But not everything is so simple.

The fact is that when one of the lamps goes out, the protection on the PWM controller of the inverter will work, and the backlight, and most often the entire monitor, will turn off. Therefore, when repairing LCD monitors and televisions, if there is a suspicion of an inverter or lamps, it is necessary to check each of the lamps with a test inverter. I purchased such a test inverter on Aliexpress as in the photo below:

Test inverter with Ali express

This test inverter has a connector for connecting an external power supply, wires with crocodiles at the output, and connectors for connecting plugs, monitor lamps. There is information on the network that such lamps can be checked for operability using an electronic ballast from energy-saving lamps, with a burned-out lamp spiral, but having working electronics.

Electronic ballast from an energy-saving lamp

What if, using a test inverter or electronic ballast from an energy-saving lamp, you found out that one of the lamps has become unusable and does not light up at all when connected? You can, of course, order lamps on Aliexpress, by the piece, but given that these lamps are very fragile, and knowing the Russian Post, you can easily assume that the lamp will come broken.

Broken Matrix LCD Monitor

You can also remove the lamp from a donor, such as a monitor with a broken matrix. But it is not a fact that such lamps will last a long time, since they have already partially exhausted their resource. But there is another option, a non-standard solution to the problem. You can load one of the outputs from transformers, and there are usually 4 of them, according to the number of lamps on 17 inch monitors, resistive or capacitive load.

Power supply and monitor inverter board

If everything is clear with a resistive one, it can be an ordinary powerful resistor, or several connected in series or in parallel, in order to gain the required rating and power.But this solution has a significant drawback - resistors will generate heat when the monitor is operating, and given that it is usually hot inside the monitor case, additional heating may not please electrolytic capacitors, which, as you know, do not like prolonged overheating and swell.

Swollen capacitors monitor power supply

As a result, if it were, for example, a 400-volt network electrolytic capacitor, that same big barrel known to everyone from the photo, we could get a burnt-out mosfet or a PWM controller microcircuit with a built-in power element. So, there is another way out: to extinguish the required power using a capacitive load, a capacitor 27 - 68 PicoFarad and an operating voltage of 3 Kilovolts.

This solution has some advantages: there is no need to place bulky heating resistors in the case, but it is enough to solder this small capacitor to the contacts of the connector to which the lamp is connected. When choosing the rating of the capacitor, be careful not to solder any ratings, but strictly according to the list at the end of the article, in accordance with the diagonal of your monitor.

We solder the capacitor instead of the backlight lamp

If you solder a smaller capacitor, your monitor will turn off as the inverter will still go into protection due to the fact that the load is small. If you solder a larger capacitor, the inverter will work with overload, which will negatively affect the service life of the mosfets at the output from the PWM controller.

If the mosfets are broken, the backlight, and possibly the entire monitor, will also not be able to turn on, since the inverter will go into protection. One of the signs of overloading the inverter will be extraneous sounds coming from the inverter board, such as hiss. But with the VGA cable disconnected, sometimes a slight hiss coming from the inverter board is normal.

Selection of capacitor ratings for the monitor

The photo above shows imported capacitors, there are also their domestic counterparts, which usually have a slightly larger size. I once soldered ours, domestic at 6 KiloVolts - it all worked. If your radio store does not have capacitors for the required operating voltage, but there are, for example, 2 KiloVolts, you can solder 2 capacitors 2 times larger in series, while their total operating voltage will increase and allow them to be used for our purposes.

Likewise, if you have capacitors 2 times smaller, 3 Kilovolts, but not at the required rating, you can solder them in parallel. Everyone knows that series and parallel connection of capacitors are considered according to the inverse formula of series and parallel connection of resistors.

Parallel connection of capacitors

In other words, when capacitors are connected in parallel, we use the formula for the series connection of resistors or their capacitance is simply added, with a series connection, the total capacitance is calculated using a formula similar to the parallel connection of resistors. Both formulas can be seen in the figure.

DIY monitor repair

Many monitors were already directed in a similar way, the backlight brightness dropped slightly, due to the fact that the second lamp on top or bottom of the monitor or TV matrix still functions and gives, albeit less, but sufficient illumination so that the image remains quite bright.

Condensers in the online store

Such a solution for home use may well suit a novice radio amateur, as a way out of this situation, if the alternative is to repair in a service costing one and a half to two thousand, or buy a new monitor. These capacitors cost only 5-15 rubles per piece in radio stores in your city, and any person who knows how to hold a soldering iron in their hands can perform such repairs. Successful repairs to everyone! Especially for Radioskot.ru - AKV.

Repair CRT Monitor on their own and at home, perhaps knowing the most common common breakdowns and how to remove them.

If you have an old, broken CRT monitor at home or at work, do not rush to throw it away. Many monitors of these old editions can be used, for example, for video surveillance or for video processing, especially since the color rendition of these types of monitors is much richer than that of LSD monitors, and if necessary, you can still sit at them well.

Now we will analyze the most common reasons for the failure of these types of monitors, and how to repair a CRT monitor at home with our own hands.

• The monitor does not turn on, a fuse may have blown, the power cable is faulty, an open circuit in the power supply circuit, which must be soldered.

• Over time, the color rendition and image quality deteriorate; here you can calibrate and demagnetize the ray tube.

• The whistle when the monitor is turned on is a signal that it is time to re-solder the capacitors in one of the units.

• When turned on, there is no signal to the ray tube, in this case it is necessary to remove the monitor case and clean everything from dust, solder the tracks on the printed circuit board, if they come off, replace the swollen capacitors, view the field-effect transistors and start relays.

• When the monitor is connected to a computer, a message appears that there is no signal or no connection was found, in this case it is necessary to replace the VGA cable.

When you repair a CRT monitor, follow safety precautions and remember to unplug the power cord.
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Write in the comments below what is the malfunction of your CRT monitor. And did you manage to fix it.

Here are the TOP 10 most common LCD monitor malfunctions that I felt the hard way. The fault rating was compiled according to the author's personal opinion, based on the experience of working in the service center. You can take this as a universal repair manual for almost any LCD monitor from Samsung, LG, BENQ, HP, Acer and others. Here we go.

I divided the malfunctions of LCD monitors into 10 points, but this does not mean that there are only 10 of them - there are many more, including combined and floating ones. Many of the breakdowns of LCD monitors can be repaired by hand or at home.

in general, although the power indicator may be blinking. At the same time, twitching the cable, dancing with a tambourine and other pranks do not help. Tapping the monitor with a nervous hand usually doesn't work either, so don't even try. The reason for such a malfunction of LCD monitors is most often the failure of the power supply board, if it is built into the monitor.

Recently, monitors with an external power source have become fashionable. This is good because the user can simply change the power supply in the event of a breakdown. If there is no external power source, then you will have to disassemble the monitor and look for a malfunction on the board. In most cases, it is not difficult to disassemble an LCD monitor, but you need to remember about safety.

Before fixing the poor fellow, let him stand for 10 minutes, unplugged. During this time, the high-voltage capacitor will have time to discharge. ATTENTION! DANGEROUS TO LIFE if the diode bridge and the PWM transistor burn out! In this case, the high voltage capacitor will not discharge in an acceptable time.

Therefore, EVERYONE before repairing to check the voltage on it! If a dangerous voltage remains, then the capacitor must be manually discharged through an insulated resistor of about 10 kOhm for 10 seconds. If you suddenly decide to close the terminals with a screwdriver, then keep your eyes away from sparks!

Next, we proceed to inspect the monitor power supply board and change all burned-out parts - these are usually swollen capacitors, blown fuses, transistors and other elements. It is also MANDATORY to solder the board or at least inspect the soldering under a microscope for microcracks.

From my own experience I will say - if the monitor is more than 2 years old - then 90% that there will be microcracks in the soldering, especially for LG, BenQ, Acer and Samsung monitors. The cheaper the monitor, the worse it is made at the factory. Up to the point that the active flux is not washed out - which leads to the failure of the monitor after a year or two. Yes, yes, just when the guarantee ends.

when the monitor is turned on. This miracle directly indicates to us a malfunction of the power supply.

Of course, the first step is to check the power and signal cables - they must be securely fastened in the connectors. A blinking image on the monitor tells us that the monitor backlight voltage source is constantly jumping off the operating mode.

The most common reason for this is swollen electrolytic capacitors, microcracks in the solder and a faulty TL431 microcircuit. Swollen capacitors most often cost 820 uF 16 V, they can be replaced with a larger capacity and a higher voltage, for example, the cheapest and most reliable ones are Rubycon 1000 uF 25 V capacitors and Nippon 1500 uF 10 V capacitors. 105 degrees) Nichicon 2200 uF 25 V. Everything else will not last long.

after the time has elapsed or does not turn on immediately. In this case, again, there are three frequent malfunctions of LCD monitors in order of frequency of occurrence - swollen electrolytes, microcracks in the board, faulty TL431 microcircuit.

With this fault, a high-frequency squeak of the backlight transformer can also be heard. It usually operates at frequencies between 30 and 150 kHz. If the mode of its operation is violated, oscillations can occur in the audible frequency range.

but the image is viewed under bright light. This immediately tells us about a malfunction of LCD monitors in terms of the backlight. In terms of the frequency of occurrence, it could be put in third place, but it has already been taken there.

Option two - either the power supply and inverter board burned out, or the backlight lamps are faulty. The latter reason is not common in modern monitors with LED backlighting. If the LEDs are backlit and fail, then only in groups.

In this case, there may be a darkening of the image in places at the edges of the monitor. It is better to start repairs with diagnostics of the power supply and inverter. An inverter is the part of the board that is responsible for the formation of a high-voltage voltage of the order of 1000 volts to power the lamps, so in no case should you try to repair the monitor under voltage. You can read about repairing the Samsung monitor power supply in my blog.

Most monitors are similar in design, so there shouldn't be any problems. At one time, monitors simply rained down with a breakdown in contact near the tip of the backlight. This is treated with the most careful disassembly of the matrix to get to the end of the lamp and solder the high voltage wires.

If the backlight itself burns out, I would suggest replacing it with the LED backlight bar that usually comes with your inverter. If you still have questions - write to me by mail or in the comments.

These are the nastiest LCD monitor malfunctions in the life of any computer technician and user, because they tell us that it's time to buy a new LCD monitor.

Why buy new? Because your pet's matrix is ​​90% unusable. Vertical stripes appear when the contact of the signal loop with the contacts of the matrix electrodes is broken.

This can only be cured by careful application of anisotropic adhesive tape. Without this anisotropic glue, I had a bad experience repairing a Samsung LCD TV with vertical stripes. You can also read how the Chinese repair such strips on their machines.

An easier way out of this unpleasant situation can be found if your brother-in-law friend has the same monitor lying around, but with faulty electronics. It will not be difficult to blind from two monitors of similar series and the same diagonal.

Sometimes even a power supply unit from a monitor with a larger diagonal can be adapted for a monitor with a smaller diagonal, but such experiments are risky and I do not recommend starting a fire at home. Here in someone else's villa - that's another matter ...

Their presence means that the day before, you or your relatives had a fight with the monitor because of something outrageous.

Unfortunately, household LCD monitors do not provide shockproof coatings and anyone can offend the weak. Yes, any decent poke with a sharp or blunt object into the LCD monitor matrix will make you regret it.

Even if there is a small trace or even one broken pixel, over time, the spot will begin to grow under the influence of temperature and voltage applied to the liquid crystals. Unfortunately, it will not work to restore the dead pixels of the monitor.

That is, there is a white or gray screen on the face. First, you should check the cables and try connecting the monitor to a different video source. Also check if the monitor menu is displayed on the screen.

If everything remains the same, we look closely at the power supply board. In the power supply unit of the LCD monitor, voltages of 24, 12, 5, 3.3 and 2.5 volts are usually formed. It is necessary to check with a voltmeter if everything is in order with them.

If everything is in order, then we carefully look at the video signal processing board - it is usually smaller than the power supply board. It has a microcontroller and auxiliary elements. You need to check if food comes to them. With one probe, touch the contact of the common wire (usually along the contour of the board), and with the other, go over the terminals of the microcircuits. Usually food is somewhere in the corner.

If everything is in order in the power supply, but there is no oscilloscope, then we check all the monitor loops. There should be no carbon deposits or darkening on their contacts. If you find something, clean it with isopropyl alcohol. In extreme cases, you can clean it with a needle or scalpel. Also check the ribbon cable and the board with the monitor control buttons.

If all else fails, then perhaps you are faced with a case of a failed firmware or a failure of the microcontroller. This usually happens from surges in the 220 V network or simply from aging of the elements. Usually, in such cases, you have to study special forums, but it's easier to start up for spare parts, especially if you have a familiar karate fighter fighting against objectionable LCD monitors.

This case is easily treated - you need to remove the frame or the back cover of the monitor and pull out the board with buttons. Most often, there you will see a crack in the board or in the solder.

Sometimes there are faulty buttons or a loop. A crack in the board violates the integrity of the conductors, so they need to be cleaned and soldered, and the board must be glued to strengthen the structure.

This is due to aging of the backlight lamps. According to my data, LED backlighting does not suffer from this. Deterioration of the parameters of the inverter is also possible due to aging of the constituent components.

This is often due to a bad VGA cable without an EMI suppressor - a ferrite ring. If replacing the cable does not work, then power supply interference may have entered the imaging circuits.

Usually they get rid of them schematically by using filtering capacities for power supply on the signal board. Try to replace them and write to me about the result.

This completes my wonderful rating of the TOP 10 most common LCD monitor malfunctions. Most of the breakdown data is collected from repairs of popular monitors such as Samsung, LG, BENQ, Acer, ViewSonic and Hewlett-Packard.

This rating, it seems to me, is also true for LCD TVs and laptops. What is your situation on the LCD monitor repair front? Write on the forum and in the comments.

The most common questions when disassembling LCD monitors and TVs - how to remove the frame? How do I release the latches? How to remove the plastic from the case? etc.

One of the wizards made a nice animation explaining how to disengage the latches from the chassis, so I'll leave it here - it will come in handy.

To view animation - click on the image.

Recently, monitor manufacturers are increasingly completing new monitors with external power supplies in a plastic case... I must say that this makes it easier to troubleshoot LCD monitors by replacing the power supply. But it complicates the operating mode and the repair of the power supply itself - they often overheat.

I showed how to disassemble such a body in the video below. The method is not the best, but it is fast and can be done with improvised means.

1.) The malfunction periodically occurs on monitors of different manufacturers and different diagonals. Outwardly, the malfunction looks like a periodic increase in brightness and a simultaneous deterioration of the sharpness of the image and its increase in horizontal and vertical directions. The cause of the problem is a capacitor leak in the screen signal circuit. A capacitor is connected directly to this signal and the other pin is connected to ground. The capacitance of the capacitor is about 10n. Replacing the capacitor will completely restore the monitor's functionality.

Korolev Andrey Mikhailovich

2.) Samsung 3NE Fault: Large and not adjustable horizontally. Fault detection: The TDA4850 microcircuit and the regulator itself are in good order. Checking the voltages showed no voltage on the Q408 MJE800 collector (NF / S-L, 60V, 4A, 40W, B> 750 analogs BD677, BD777, 2N6038..6039). A detailed search showed a malfunction of the protective diode D407 UF5404 (400V analogs of EGP30G, FE3H). Remedy: The diode was replaced with a Russian KD411A and the performance was restored.

3.) monitors (G50 Model 6543-302), the main malfunction is the loss of horizontal sync and a long warm-up when turned on. The reason is the drying out of a 1000x25V capacitor located between two powerful diodes in cases like KREN5.

4.) The SAMSUNG 3NE monitor does not start, the effect of overloading the power supply. Broken diode D607 RGP02-12E in the collector circuit of the key transistor or IC KA2H0880. Replaced with Soviet KD226G, the monitor worked without problems.

5.) Video monitors output voltages are 2 times higher than the norm as a result of the output from the standing vertical, horizontal scan, RGB amplifier on the kinescope board (lm1203n). The power supply is assembled for ms 3842 (dcdc converter). CAUSE breakage of the 150k resistor in the msx 3842 circuit on a small board.

12.) Brige CAE3645G Periodically appearing "twist on top" Personnel MS is in good order, electrolytes in the piping too. Diode D401 (1N4002) is faulty. Several of these were already.

13.) 17-inch ACER ASPIRE multimedia when the ambient temperature rises, the sound amplifier claps. The drawback of the project - there is a powerful transistor of the power supply next to the sound - it is eliminated by gluing a heatsink to the TDA1524 - or installing a fan from a 486 processor. Replacing the microcircuits is useless. All parts are in good working order, voltage is normal.

14.) The following malfunction may be observed in Hyundai S570 monitors: the monitor seems to work without problems, but periodically it starts to “click” (as if the protection is triggered, then demagnetization) and so on until you turn it off. After switching on, everything is again in perfect order. It can be repeated once a month, or every day. The reason is the WT60P1 processor. You can replace the processor, or you can shield it from the monitor (in most cases it helps a lot). Information for firms that carry out warranty repairs - the processor crashes due to static, and in 90% of cases this means that the monitor was plugged into an outlet without grounding, and this is a violation of the operating conditions (well, then - withdrawal from the warranty, paid repairs and etc.)

15.) Samsung 550S. External manifestation - the monitor does not turn on. Diode D406 (DG3) breaks down. I recommend changing to something thicker, for example RU4DS.

16.) Hyundai S560. External manifestation - twitching of the vertical scan, over time - resizing and disappearing. There is a reaction to tapping on the body.It is necessary to solder the frame scan m / s (I do not remember the type). Uncle Kim, when assembling, first soldered m / s, and then screwed on the radiator. The result is annular cracks in the soldering.

17.) Samsung SyncMaster 410b. Only red was displayed. The reason was the “forgetfulness” of the EEPROM 24C02 (256 * 8). The factory default brightness and contrast settings for each color have been erased. We solder it, put it on the panel. It is treated with any programmer (I have a COMPic) working with 24C (LC) 02 (we also check the validity of the EEPROM). EEPROM addresses and their meanings
————————————–
0xF6 - overall brightness (current)
0xF7 - overall contrast (current)
factory:
0xF8 - RED contrast
0xF9 - GREN contrast
0xFA - contrast by BLUE
0xFB - brightness by RED
0xFC - brightness by GREEN
0xFD - brightness by BLUE

A “normal” picture for “my” monitor turned out when all the contrast (addresses 0xF8-0xFA) were set to 0x8C, but the brightness values ​​for each color had to be selected in the programmer until an acceptable white balance was obtained (range 0x60-0x85)

P / S Working firmware is included in the archive with firmware.

18. On many models of monitors that have been in operation for more than 4-5 years, the filament rectifier capacitor dries out. In this case, the monitor screen does not light up or glows very weakly (as when the cathode is worn out), and the constant component of the filament voltage is 3..5 volts.

Krasimir Krastev (Bulgaria)

19. In PREVIEV monitors, the MOS transistor for horizontal raster correction often breaks down - while the raster is compressed, there is no horizontal size adjustment and horizontal correction.

Krasimir Krastev (Bulgaria)

20. The PREVIEV monitors often fail the MOS transistor and Schottky diode in the second switching power supply for powering the horizontal scan. The defect manifests itself as a knocking or buzzing in the area of ​​the pulse transformer. In this case, the power LED blinks or the power supply does not start at all.

Krasimir Krastev (Bulgaria)

21. Monitors and faxes, power supplies of which are built using microcircuits 3842, 3843, 3844 often do not start the power supply due to breakage of the triggering circuit resistor (200.50 KOhm) coming from the electrolyte of the 220 volt input rectifier. A rectifier diode and an electrolytic capacitor (20-100 microfarads) often fail in the same circuit. In this case, when the monitor is turned on, the power supply may beep or “poke”.

Krasimir Krastev (Bulgaria)

23. Monitor Viewsonic 641-1E. Periodic shutdowns. Usually, in such cases, C335 (0.22 mF) is changed, but this time the C311 capacitor (0.47 mF) was blown up. On the one hand, it was heated by a transistor radiator, and close to the capacitance, a powerful resistor.

25. Shamrock C505L
1. There is no image, the power supply is working, - 70 volts are not supplied to the output transistors of the video amplifiers. Reason: R395 break - 10 ohm
2. No on-screen menu (no power is supplied to U303 (M35043-051SP) on the video amplifier board) Reason: ZD301 Zener diode (5.18 volts) is broken through the +7 volt circuit.
3. No blue color Cause: broken diode D324 (1N4148) on the video amplifier board.
4. There is no synchronization of the image in the modes 800 * 640 and 1024 * 800 and above Cause: It is necessary to shield the control processor (C1883CT) with a normal screen (copper or brass), wires were thrown from one corner to another.

26. A ViewSonic P655 monitor got for repair with a defect such that when you try to change any parameters (brightness, contrast or geometry) from the front panel upwards, the “Volume” scale is displayed on the monitor. This monitor has no built-in. ULF, no speakers. It turned out that the design of the installation is as follows: the guides are very close to the river. backplane elements. As a result, when sliding the latter along the "skis" (this can also happen during assembly at the factory) into the monitor case, with a slight left-right skew, the guides can cut off the R 710 resistor. I did not find the circuits of this model and selected the nominal value experimentally - 4K3. Menu options switching is controlled via the I2C bus and, therefore, all resistor values ​​in the comparator are critical.

27. IBM 6314 breakdown: the image is periodically compressed vertically until it completely disappears, it is enough to solder the P701 connector - there are a lot of "cold" rations, externally (visually) the malfunction may not appear naturally - there are already several devices with such a breakdown

Despite the fact that recently monitors have become quite cheaper, and you can buy a decent monitor for 150 bucks, many cannot afford this either, so they use ancient monics with a diagonal of 14 and 15 inches. Such monitors are also often used for servers, where there are no special complaints about the picture. Naturally, most of these devices by themselves do not differ in special quality, and due to aging of the elements and tubes, they often work completely disgusting. Repair of most of the malfunctions of such displays is quite within the power of even an unprepared person.

Let's make a reservation right away that this material mainly concerns old monitors that have the ability to manually adjust. The fact is that this possibility is not always present. For example, most SONY monitors cannot be properly repaired and adjusted at home without special equipment.

You will need a set of good long screwdrivers (for setting), a multimeter and a soldering iron can also come in handy. The metal parts of screwdrivers must be insulated from the handle to the tip, since during the adjustment process there is a chance that something will short them out with bare parts.

Most of the malfunctions of all CRT monitors are associated with the tube, power supply, line transformer and processor. There are also mechanical malfunctions, for example, jammed power buttons, a broken signal cable, damage to the anti-reflective coating of the screen.

In old (but working) monitors, the main malfunction is a dead tube, as a result of which, even at maximum brightness and contrast settings, the image is dark and low-contrast. When the emission properties of the cathodes are uneven, it happens that one of the three primary colors is strongly weakened or absent altogether, this happens when a certain color "sits down". Also, incorrect color mixing and defocusing are often found, this happens due to the fact that over time the characteristics of many radio elements change, and the tuning gets lost.

This is one of the most critical, as well as dangerous nodes of any monitor, often referred to simply as a "line". The main function of this transformer is to supply high voltage (about 15 kV) to the kinescope anode. Various malfunctions of this transformer in many cases are the cause of the distorted image.

The monitor's power supply unit can "die" both by itself (from old age), or through the fault of another monitor unit, which, when burned out, drags the power supply unit along with it. For this reason, it is not worth taking on its repair, since without a certain experience it is impossible to trace all the interconnections between the monitor nodes and determine exactly where the malfunction came from and who is the culprit. It is best to take a monitor with power faults to a service - it will cost less than doing it yourself. An exception can be considered cases when the malfunction lies in the input circuits, and the voltage simply does not go to the monitor power supply.

In more or less modern monitors, there is always a processor that controls the operation of the monitor. He is in charge of all operating modes and auto-tuning. This processor often begins to fool, as a result of which you can observe various distortions and the inability to adjust the monitor by standard means. This also includes non-volatile memory (EEPROM), which stores the "firmware" of the monitor. Due to glitches of this firmware (for example, due to physical damage to the microcircuit), various abnormal effects and malfunctions are also possible.

If you dare to climb into the monitor on your own, remember that even after turning off the power and disconnecting the monitor from the mains, dangerous voltages are present for some time, therefore, before climbing on its insides, you need to wait about 15 minutes.

In the process of setting, you will have to poke around in the included monitor.This is perhaps the most dangerous activity you can think of, so be extremely careful! To set up, use only a well-insulated screwdriver with a comfortable handle, otherwise, due to inexperience, you can short-circuit something, which can lead to the most unexpected consequences. For example, a small explosion and fire may occur, as a result of which it will no longer be possible to repair the monitor, as well as moderate to severe injuries.

Many malfunctions of monitors, especially modern ones, are associated with engineering or technological flaws, so before doing something with the monitor, you need to go over various forums and try to determine the cause of the malfunction by the symptoms described. If the malfunction is "standard", it is quite possible that you will find a ready-made solution for its elimination (as a rule, not difficult). At the same time, you do not have to spend money on delivering the monitor to service and repair. However, if the monitor still has a warranty, it is still better to take it to the service, since by repairing the monitor yourself, you automatically lose it (of course, if you are not an employee of an authorized service center :)).

Almost all SONY monitors do not have the ability to manually adjust the anode voltage of the kinescope (Screen regulator). In order to raise the voltage, you need a special interface cable and software (search on the Internet), and instead of Screen, a second Focus regulator is most often installed (in SONY monitors with screens larger than 17 inches, a separate adjustment of focusing vertically and horizontally is used, thus you can achieve a clearer picture).

Now that the warnings have been made, let's go directly to the repair. Next, we will build the article in the order of describing the malfunction and methods for its elimination. We will move from the simplest faults to the most complex ones, gradually delving into the jungle of various methods and subtleties of this difficult exercise.

So, let's consider the case when the monitor does not turn on at all, while no suspicious sounds are heard from the womb of the device, the operation indicator does not light up and does not blink.

Perhaps the problem lies in the input power circuits. In this case, the fix cannot even be called a repair - all that is needed in this case is to check why 220 volts do not reach the monitor power supply. Very often in old moniks, power switches fail. You also need to check the contacts and fuse. Then you should carefully inspect the printed circuit board for various fires and, if there are none, trace the "path" of 220 volts from the input connector to the power supply, checking each element in this circuit. If you have a multimeter and are confident in yourself, you can, by plugging the monitor into the network, sequentially check the voltages in different parts of the circuit - this is much easier and faster.

In the event of a power switch malfunction (provided that this switch has two positions, that is, it is fixed in the on position), you can simply solder its contacts with a piece of wire, very often it is much easier than finding the same switch.

If the fuse has blown, do not rush to wind a "bug" on it - first you need to find out why it burned out. With the same probability, this reason could be a power surge or a power supply burnout. To check this, it is best to replace the burned-out fuse with a new fuse, rated for the same amperage as the one that was there earlier. If there is no fuse, and the nearest store is 100 km away, you can try to remove a thin metal hair from the stranded wire and wind it around the contacts of the fuse holder. If the bug / fuse burns out when the monitor is turned on, you will have to take the monitor to a service, or, alternatively, with patience, blindly change most of the power supply, making sure that the cause of the PSU burnout does not lie in the monitor circuit. Note that it is useless to check the resistance of the power input without understanding the circuit design - first you need to turn off the demagnetizing loop, otherwise, due to the design features of many monitors, the multimeter will show a short circuit.

Also, sometimes there is a situation when the monitor does not see the computer at close range and assures that there is no signal. This usually happens due to damage to the signal cable, and if the cable is shaken, contact is temporarily restored. Actually, this is the only way to quickly check the cable. If everything is in order with the cable, but the monitor stubbornly does not recognize that it is connected to the computer, the problem lies in the video signal input circuits. With such breakdowns, definitely, to the service.

CRT (cathode-ray tube) Is one of the most difficult and therefore most unreliable parts of a monitor. Most of the breakdowns are associated precisely with its shortcomings and malfunctions. What kind of shamanism is not resorted to in service centers to restore a damaged picture tube! One of the most common CRT malfunctions is the deterioration of the emission properties of cathodes. At the same time, the characteristics of electron guns deteriorate, in other words, they gradually lose the ability to emit electrons, which bombard the phosphor layer on the inner side of the screen, which is reflected in the deterioration of the monitor brightness. It is about such a pipe that they say that it "sat down".

There are several ways to prolong the agony of the monitor indefinitely (most often about a year), namely, in some way to restore the properties of the kinescope, or to compensate for its shortcomings. Let's make a reservation right away that a shrunken kinescope cannot be returned to its original state in any case. There are some exceptions to this rule, but they apply to non-hooking problems. Depending on the condition at the time of repair, the restored condition of the tube can last from several months to two years on average.

The first and easiest way is to raise the anode voltage. In this case, the electrons begin to move faster from the cathode to the anode, and as a result, the brightness of the screen increases. Unfortunately, in this case the rate of cathode degradation increases even more, although in such cases there is nothing to lose.

Another widely used method is to shoot the cathodes of the tube with a high voltage. In this case, temporarily (the period is usually unpredictable), the properties of the cathodes are restored. This method is used for practically dead tubes, which are no longer helped by raising the voltage. As you already guessed, we will deal with raising the tension.

The voltage adjustment unit is located on the line transformer. This is always the largest transformer in the monitor, a thick red wire with a suction cup attached to the tube body extends from it. This transformer usually contains two controls, Focus and Screen. Do not touch the Focus knob yet (we will deal with it later), now we are interested in the Screen knob - it is with its help that the anode voltage is regulated. First, turn the brightness and contrast of the monitor to maximum, then use a screwdriver to turn the regulator clockwise and counterclockwise. Having found the desired direction in this way (while, of course, looking at the screen), select such a value so that the picture is bright enough for comfortable work, but in no case leave a margin of brightness - the more voltage at the anode, the faster the tube will creep to the cemetery.

By the way, if you are unable to smoothly rotate the engine, you need to vigorously twist it several times in different directions to the limit.

Convergence of beams, like focusing, is static and dynamic. The static convergence is adjusted by the ring magnets on the tube throat. Dynamic convergence is carried out by the windings of the deflection system. The flattening is also adjusted by tuning variable resistors located above the deflection system and, in some cases, resistors located on a board mounted at the end of the throat. The knocked down looks like borders of undefined color on the outlines of desktop shortcuts.If you turn on the convergence test in Nokia monitor test, you will see that crosshairs of different colors creep on top of each other, forming an undefined color in the “creep” zone. In this case, you need to set up the mixing in such a way that this does not happen.

Most old monitors revive without problems using the methods described in the article. Of course, all methods are given briefly. To more or less seriously expand the description of repairs of such complexity, a whole magazine would be needed. However, having received and comprehended this information and using the search engine, you can independently find a solution to many problems associated with monitor repairs.