In most cases, the reason that the monitor does not turn on or there are problems with the image is the incorrect operation of the video card, incorrect settings, or an incorrect connection.
The simplest check:
In this case, the monitor is most likely working properly. Of course, there are possible exceptions.
You can also check the health of the monitor by connecting it to another computer.
If the monitor has proven to be inoperable, you should contact the service for diagnostics and repair. Our article will tell you what to pay attention to when describing the problem, so that during a telephone conversation you will be correctly advised on the price and timing of repairs.
Before calling the repair shop, find out the exact model name of your monitor. A number of models have standard faults that have long been known to service center employees.
The monitor does not turn on, the power indicator does not light up
If the monitor shows no signs of life, there is likely a power problem. Most often, this breakdown is easily fixed.
There may be a problem with the monitor's power cable or connectors. In this case, if you change the position of the power cord, the indicator may light up briefly when contact is made. If it is completely inoperable, the power supply will most likely need to be repaired.
Power indicator blinks, no picture
Flashing of the voltage indicator (cyclic power on and off) regardless of the position of the cord is a signal of incorrect operation of the power supply or main board.
The service center will determine the cause of the problem and fix it.
Power indicator is on - no image, backlight is on
Most likely the problem is with the processor board (MB) of the monitor. For diagnostics, you will have to contact a service center, since such “symptoms” do not allow you to immediately determine the cause of the malfunction. The technician will be able to give an exact answer only after examining the monitor in disassembled form.
The monitor backlight does not light up or goes out after a few minutes of operation
Sometimes the picture can be seen in reflected light, when looking at the monitor from above, from the side. The monitor responds to buttons and there is access to the menu. It is possible that immediately after turning on the monitor works, and after a few minutes the backlight turns off. The problem is in the inverter or in the backlight lamps: they burn out over time or can suddenly fail as a result of mechanical stress (for example, an impact). Repair consists of replacing the lamps or converter. For this procedure, you should choose a service meticulously: the procedure is complex, requiring a certain level of qualifications and increased accuracy from the specialist.
Screen brightness decreases and a reddish tint appears
These symptoms indicate burnout of the backlight lamps, as in the previous case. Decreased brightness and a reddish tint may occur only in a specific area of the screen or throughout the entire monitor. The problem is solved by replacing the lamps, and various dark screensavers and monitor sleep mode settings serve as preventative measures. The fewer nights the monitor sits with a static picture on, the longer the lamps will last.
Stripes on the screen
The appearance of vertical or horizontal stripes on the monitor screen is a sign of a malfunction of the decoder cables. If the stripes change location, then the problem may be in the video card, and if the stripes have a constant location and color (black, white, color), then the problem is in the monitor matrix. Technicians in service centers practically do not undertake to replace cables, since there is no confidence in the success of the operation and that the problems will not return in a short time. The only solution to the problem is to replace the matrix assembly. If your monitor is under warranty, contact service immediately after the stripes appear, even if there is only one stripe and it doesn’t bother you.
If stripes appear on a monitor whose warranty period has already expired, check with the service center for the cost and estimated repair time for your model. An original matrix is required, and the cost can be comparable to buying a new monitor.
Image or color distortion
Usually occurs due to loss of contact in the signal cable or broken connectors. Check the signal cable(VGA,DVI) by replacement.
The DVI (digital) cable can only be switched (!!!) on a de-energized monitor!!!
If the defect persists, this is most often due to either incorrect operation of the video card or a breakdown of the monitor’s processor board. In some cases it can be fixed by flashing the firmware.
The technician will be able to name the exact cause of the malfunction and the cost of repair only after diagnosis.
The monitor does not display an image from the computer, it displays messages
If, instead of the usual picture, the monitor displays a service message (“check the cable” or “non-optimal mode”), and this state does not change after the appropriate changes (replacing the cable, setting the required mode), most likely the problem is in the monitor. A number of monitor models with a MICOM processor (Samsung 710 (N/V), 713/913 lines, some Philips, LG) have a standard malfunction associated with the rapid failure of the processor. Repairing or replacing the faulty processor completely eliminates the problem.
LED monitors differ in the type of backlighting: LEDs are used instead of lamps. Failure of LEDs, which manifests itself as a decrease in brightness in a separate area of the screen, is quite rare and can be successfully repaired.
We draw your attention to the fact that slight unevenness in the backlight of LED monitors in budget models occurs already upon purchase. In this case, the center of the screen is illuminated more than the edges. This is due to the use of cheap materials to create the scattering layers of the screen. Not ideal color reproduction is also a feature of LED monitors; they are simply not designed for professional color work.
One of the common failures of LED monitors is screen flickering, which becomes noticeable when the brightness is reduced. For some models, repairs are limited to flashing the firmware; for others, the processor board needs to be replaced.
Acceptance of applications from 8:00 to 23:00
A little about dead pixels!
Often in LCD, LED and even OLED TVs there are defects such as Dead pixel.
It usually looks like a dot in an arbitrary area of the screen, of any color.
There are 4 types of “dead pixels”:
*Dead pixels- these are pixels that do not light up (always turned off). On a white background it looks like a black dot.
*Hot pixels- on the contrary, they are always on and on a black background they look like a white dot.
*Stuck pixels may light up red, blue, green or yellow. This happens because some of the subpixels are always on or always off.
*Group of defective pixels- these are several defective pixels in a 5x5 pixel square.
(click on image for larger view)
Many stores offer TV screen testing for a fee. Of course, this procedure will provide you with a more comfortable viewing experience. But not many people prefer to overpay for something that is easy to produce on their own.
Checking using a USB flash drive
Using these images, you can check your TV for manufacturing defects such as:
Copy these images to a USB drive and connect it to the USB port of your TV.
Using the built-in media player, scroll through all the pictures - the matrix defect will be much easier to notice!
If there is a dead pixel, you will definitely see it in the form of a black, white or colored dot in any area of the screen.
Checking using a Laptop
You can also use a special program to test your TV or monitor screen
To do this, you need to connect the TV to your computer or laptop using an HDMI cable and run the program.
This program allows you to evaluate not only the presence or absence of dead pixels on the display, but also the uniformity of the matrix backlight, geometric distortions and matrix response time.
You can download a program to check your TV screen for dead pixels using the link: DOWNLOAD
Check with a Professional
You can Call a wizard to set up your TV, as well as checking your TV or monitor screen for dead pixels!
If you want to exchange an already purchased monitor with dead pixels, keep in mind that there is an international standard ISO 13406-2 regulating the permissible number defective pixels on the LCD monitor. Thus, the seller may refuse to exchange your monitor or refund your money if the number of defective pixels is .
1The permissible number of defective pixels depends on the display class (pixel fault class). The ISO 13406-2 standard distinguishes four classes: first does not allow the presence of defective pixels. As a rule, everything is modern LCD monitors relate to second grade. Below you can calculate the acceptable number of defective pixels according to the ISO 13406-2 standard for monitors second class:
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Note. In the calculation, the fractional number of defective pixels is rounded to a whole number by discarding the fractional part.
The ISO 13406-2 standard identifies the following defects: always-on white pixels (type I), always-off black pixels (type II), subpixel defects (type III), which appear as colored pixels always on/off in primary colors (red, green). , blue, cyan, magenta, yellow).
In addition, for resolutions of 1 million and higher, accumulation of color defective pixels (type III) is allowed nearby in a 5 x 5 pixel square. This defect is called a cluster. Second class monitors does not allow the presence of 5 x 5 clusters with defective pixels of type I or II. For more details see.
In practice, such a large number of defective pixels as specified in ISO 13406-2 is extremely rare. The wide tolerance can be explained by the fact that the standard was developed in 2000. Since then, LCD panel manufacturing technologies have undergone improvements.
2Examination LCD monitor on presence of defective pixels consists of carefully examining the screen to identify abnormal pixels. The inspection is carried out sequentially for the primary colors: black, white, red, green, blue, cyan, magenta and yellow.
Good day.
A monitor is a very important part of any computer, and not only ease of use, but also vision depends on the quality of the picture on it. One of the most common problems with monitors is the presence dead pixels.
Dead pixel - this is a point on the screen that does not change its color when the picture changes. That is, it burns with white (black, red, etc.) color, without conveying color, and it burns. If there are many such points and they are in prominent places, it becomes impossible to work!
There is one nuance: Even when buying a new monitor, you may be given a monitor with dead pixels. The most annoying thing is that a few dead pixels are allowed by the ISO standard and returning such a monitor to the store is problematic...
In this article I want to talk about several programs that allow you to test your monitor for dead pixels (well, and protect you from buying a low-quality monitor).
I sMyLcdOK (best dead pixel search utility)
Rice. 1. Screenshots from IsMyLcdOK during testing.
In my humble opinion, this is one of the best utilities for finding dead pixels. After launching the utility, it will fill the screen with different colors (as you press numbers on the keyboard). You just need to look carefully at the screen. As a rule, if there are dead pixels on the monitor, you will immediately notice them after 2-3 “fills”. In general, I recommend it for use!
Advantages:
D ead Pixel Tester (translation: dead pixel tester)
Another very interesting utility that quickly and easily finds dead pixels. The program also does not require installation, just download and run. Supports all popular versions of Windows (including 10).
To start the test, just launch the color modes, change pictures, select fill options (in general, everything is done in a small control window, you can close it if it gets in the way). I like the auto mode better (just press the “A” key) - and the program will independently change the colors on the screen at short intervals. Thus, in just a minute, you will decide whether to buy a monitor...
Monitor test (online monitor check)
In addition to programs that have already become a kind of standard when checking a monitor, there are also online services for searching and detecting dead pixels. They work on a similar principle, the only difference being that you (for verification) will need the Internet to access this site.
Which, by the way, will not always be possible to do - since the Internet is not available in all stores where they sell equipment (connect a flash drive and run a program from it, and in my opinion, it’s faster and more reliable).
As for the test itself, everything is standard here: we change the colors and look at the screen. There are quite a lot of checking options, so with a careful approach, not a single pixel will escape!
By the way, the same site also offers a program for downloading and running directly on Windows.
If after purchase you find a dead pixel on the monitor (and even worse, if it is in the most visible place), then returning it to the store is very difficult. The bottom line is that if you have less than a certain number of dead pixels (usually 3-5, depending on the manufacturer), then they may refuse to change your monitor (in such cases).
Happy shopping :)
Here are the TOP 10 most common malfunctions of LCD monitors that I have personally experienced. The rating of malfunctions was compiled according to the personal opinion of the author, based on his experience working in a 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 of them, including combined and floating ones. Many of the breakdowns of LCD monitors can be repaired with your own hands and at home.
at all, although the power light may blink. In this case, the monitor lights up for a second and goes out, turns on and turns off immediately. In this case, tugging at the cable, dancing with a tambourine and other pranks do not help. The method of tapping the monitor with a nervous hand usually doesn’t help either, so don’t even try. The reason for this 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 supply have become fashionable. This is good because the user can simply change the power source in case of breakdown. If there is no external power source, you will have to disassemble the monitor and look for a fault on the board. in most cases it is not difficult, but you need to remember about safety precautions.
Before fixing the poor guy, let him stand for 10 minutes, unplugged. During this time, the high-voltage capacitor will have time to discharge. ATTENTION! It is DANGEROUS TO LIFE if the PWM transistor also burns out! In this case, the high-voltage capacitor will not discharge in an acceptable time.
Therefore, EVERYONE check the voltage on it before repairing! If dangerous voltage remains, then you need to discharge the capacitor manually through an insulated one of about 10 kOhm for 10 seconds. If you suddenly decide to short-circuit the leads, then protect your eyes from sparks!
Next, we proceed to inspect the monitor’s power supply board and replace all burnt 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 that if the monitor is more than 2 years old, then 90% 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. To the extent that the active flux is not washed away - which leads to failure of the monitor after a year or two. Yes, yes, just when the warranty ends.
when you turn on the monitor. This miracle directly indicates to us that the power supply is faulty.
Of course, the first thing you need to do is check the power and signal cables - they must be securely fastened in the connectors. A flickering image on the monitor tells us that the monitor's backlight voltage source is constantly jumping out of operating mode.
after the time has elapsed or does not turn on immediately. In this case, again, there are three common malfunctions of LCD monitors in order of frequency of occurrence - swollen electrolytes, microcracks in the board, faulty microcircuit.
With this malfunction, a high-frequency squeak from the backlight transformer can also be heard. It typically operates at frequencies between 30 and 150 kHz. If its operating mode is disrupted, vibrations can occur in the audible frequency range.
but the image is visible under bright light. This immediately tells us that LCD monitors are faulty in terms of backlighting. In terms of frequency of occurrence, it could be placed in third place, but it is already taken.
There are two options - either the power supply and inverter board burned out, or the backlight lamps are faulty. The last reason is not common in modern monitors. If the LEDs in the backlight fail, then only in groups.
In this case, the image may darken in places at the edges of the monitor. It is better to start repairs by diagnosing the power supply and inverter. The inverter is that part of the board that is responsible for generating a high-voltage voltage of about 1000 Volts to power the lamps, so under no circumstances should you try to repair the monitor under voltage. You can read about it on my blog.
Most monitors are similar in design, so there shouldn't be any problems. At one time, monitors simply fell off due to poor contact near the tip of the backlight. This can be cured by carefully disassembling the matrix in order to get to the end of the lamp and solder the high-voltage wiring.
A simpler way out of this unpleasant situation can be found if your friend-brother-matchmaker has the same monitor lying around, but with faulty electronics. It won’t be difficult to make two monitors of similar series and the same diagonal.
Sometimes even the power supply 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. But in someone else’s villa, that’s a different matter...
Their presence means that the day before you or your relatives had a fight with the monitor over something outrageous.
Unfortunately, household LCD monitors are not equipped with shockproof coatings, and anyone can offend the weak. Yes, any decent poke with a sharp or blunt object will make you regret it.
Even if there is a small trace or even one broken pixel left, the stain will still begin to grow over time under the influence of temperature and voltage applied to the liquid crystals. Unfortunately, it is not possible to restore dead monitor pixels.
That is, a white or gray screen appears on your face. First, you should check the cables and try connecting the monitor to another video source. Also check whether the monitor menu is displayed on the screen.
If everything remains the same, look carefully at the power supply board. The power supply of an LCD monitor usually generates voltages of 24, 12, 5, 3.3 and 2.5 Volts. You need to use a voltmeter to check if everything is okay with them.
If everything is in order, then carefully look at the video signal processing board - it is usually smaller than the power supply board. It contains a microcontroller and auxiliary elements. You need to check if they are getting food. Touch the contact of the common wire with one (usually along the outline of the board), and with the other, walk along the pins of the microcircuits. Usually the food is somewhere in the corner.
If everything is in order regarding the power supply, but there is no oscilloscope, then we check all the monitor cables. 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 board with the monitor control buttons.
If all else fails, then perhaps you are faced with a case of broken firmware or microcontroller failure. 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 use them for spare parts, especially if you know a familiar karateka who fights against unwanted LCD monitors.
This case can be easily treated - you need to remove the frame or back cover of the monitor and pull out the board. Most often there you will see a crack in the board or in the solder.
Sometimes there are faulty or . 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 occurs due to aging of the backlight bulbs. According to my data, LED backlight does not suffer from this. It is also possible that the parameters of the inverter may deteriorate, again due to the aging of the components.
This often happens due to a bad VGA cable without an EMI suppressor -. If replacing the cable does not help, then it is possible that power interference has penetrated into the imaging circuits.
Usually they are eliminated from the circuit design by using filter capacitors for power supply on the signal board. Try replacing them and write to me about the result.
This concludes my wonderful rating of the TOP 10 most common malfunctions of LCD monitors. The bulk of data on breakdowns was collected based on repairs of such popular monitors as Samsung, LG, BENQ, Acer, ViewSonic and Hewlett-Packard.
This rating, it seems to me, is also valid for and. What is your situation on the LCD monitor repair front? Write to and in the comments.
Sincerely, Master Pike.
The most common questions when disassembling LCD monitors and TVs are how to remove the frame? How to release the latches? How to remove the plastic case? etc.
One of the craftsmen made a good animation explaining how to remove the latches from engagement with the body, so I’ll leave it here - it will come in handy.
To view animation— click on the image.
