We turn an old monitor into a TV. We turn a monitor into a TV with our own hands How to make a TV from a laptop display

Surely many of you, having bought yourself new monitor, wondered what can be done from an old monitor. I was puzzled by this thought too, although I was puzzled by this thought for a very long time, but then there was not such a big choice various devices... But the Chinese brothers are not asleep and invent devices with an unprecedented combination of possibilities. One of these devices was a set-top box, which I purchased to add features to an old TV.

• Nexbox A95X TV Box: we make Smart TV from a regular TV

But having connected the TV to the set-top box, I was a little disappointed in the clarity of the picture, it was difficult to use the set-top box, but I helped out possibility remote control from smartphone or tablet... As a result, the prefix exceeded my expectations because it was taken to watch a heap of videos with home server, but the functionality of the set-top box turned out to be much wider and as a result, this small box turned a simple TV set into a computer remote controlled DU... Why am I all this? Read on and you will understand everything.

Since my parents do not like to throw away equipment, the Samsung SyncMaster monitor (CRT monitor), after purchasing an LCD monitor, was carefully taken away for storage in a barn in the country and was safely forgotten there. Once again putting things in order in the "trash storage" father came across a monitor and wondered if it was possible to watch the news on it at the dacha. But he could only get an answer from his advanced son, that is, from me, which he did by calling me one evening.

The monitor itself:

Since the monitor, if simplified, is a kinescope with a scanner without a radio receiver, which is in the TV, and without a sound system. In other words, this is a TV, but simplified and devoid of some parts. In fact, the monitor contains only a power supply, a scanner and a video amplifier. The only signal source is the VGA plug (D'SUB), which carries an analog signal. What does that mean? And that means we just have to find a device that will be the source of the signal.

If you have a newer monitor, then it is probably even easier with it, because some monitors, if we are talking about LCDs, were equipped with speakers, and newer ones have an HDMI input at all. If you have one, then you have a very wide range of options for making a TV out of a monitor.

First experiment: Smart TV from the monitor

Remembering that I had an adapter from HDMI to VGA lying around, I decided to look for it and, having found the adapter, I took the set-top box and went to my parents. After wiping the monitor from dust and dirt, we connected it to the mains, and then to the set-top box. Despite the small diagonal, it was very, very comfortable to use the set-top box due to the clearer picture, since the monitor, unlike the TV, is designed for high resolution and the relatively small print is easy to read.

HDMI to VGA adapter

Now you probably thought: "Cool, I'll buy myself a prefix!", But do not rush. It was just an experiment because we have no sound, VGA gives only a picture. Therefore, if you want to go this way, you will have to purchase an HDMI to VGA adapter with audio output, something like this:

You can order a similar adapter on Aliexpress, here is the link to the seller: buy an HDMI-VGA converter.

When you go to the page with products, you will only have to find the adapter that suits you, it is not at all difficult, the main thing is to pay attention to the fact that the adapter has a connector for power and audio output.

Thus, we can make a "smart TV" out of the monitor, but we will have to buy more and active speakers, which will also have to be connected to the audio jack on the adapter. As a result, we will give a second life to the monitor and get a good option for the kitchen or work.

Advantages

Within the framework of the summer residence, there are no advantages due to the lack of full-fledged communications.

disadvantages

1. This prefix is ​​useless without the Internet.
2. The cost of the set-top box.
3. The need for an adapter.
4. Lack of speakers.

Experiment 2: ordering a special TV tuner

Since the place where the barn is located is a place remote from communications and, accordingly, there is no Internet network there, thus the set-top box could not function fully there. In addition, the old father was no longer eager to master another high-tech device and asked to find a TV receiver with a remote control for him.

I present to you a wonderful device that makes a TV from a monitor:

But in the background recent events with digitalization, this prefix has lost its relevance.

Digital TV set-top box

Realizing that the availability of digital TV support for some people may be critical, a similar set-top box was found, but with different parameters. You can still connect a monitor to it, but it is no longer possible to connect a computer, and there is no audio output and built-in speaker, that is, you will have to connect external speakers.

As you can see, it looks little different from the previous version, but this is not yet a look at the back panel.

As you can see, there is still the same VGA, but besides it there is also HDMI. By the way, if you connect this set-top box via HDMI, then the sound will go through it. For example, my TV in the kitchen has HDMI, but it does not have a digital TV, and if such a set-top box is connected to it, then the sound will come from the TV. In addition, this set-top box was also equipped with a USB connector, so it becomes possible to watch videos from a flash drive and not only.

As well as the first version of the TV tuner for the monitor, this set-top box has RCA (CVBS) jacks.

But unlike the first set-top box, where this is an AV input, in this case these jacks are AV-out, that is, apart from the monitor and relatively modern TVs, this set-top box can also be connected to very old TVs.

Features of the console

Since the set-top box accepts digital TV, then, among other things, we get a lot of buns. But first, we need to find channels, this is done in an elementary way. We press the "menu" on the remote control and use the volume buttons to select the corresponding menu item (see photo):

Select "auto search" and click on the volume up button. We observe the picture:

After a while, we will see the found channels and radio stations:

The search for channels is completed, as you can see there are 20 of them in our city, in other cities the number of channels may be different.

By pressing the "info" button on the remote, you can see what is going on and what will happen next. If we press this button again, we will see more detailed information:

Using the "up" and "down" buttons we switch between gears, and with the yellow and blue buttons we scroll through the description if it is not displayed in full.

To display the program guide, we need to press "EPG" on the remote control:

Use the "left" and "right" buttons to scroll through the channels, use the "up" and "down" buttons to scroll through the programs.

And here the most interesting thing awaits us. If we press the "OK" button on a particular program, we will see a strange picture, but if we press the red button, we will see this:

This is adding a schedule to record a program. Click "OK" again and the task will be added to the queue. The most interesting thing is that we can safely turn off the set-top box, it will turn on itself and record the transmission. The only thing that is necessary for the successful completion of this task is the presence of a flash drive in the USB connector of the set-top box.

A flash drive is also required for the "timeshift" function, in Russian speaking "pause". Yes, you heard right, the set-top box can pause TV... But the set-top box will not be able to pause TV for a long time, since the volume of the recorded stream is limited by the settings of this function. By default, the volume is 1Gb, but you can increase it. This is done in the menu:

To do this, we need to select "PVR Configure" and click "OK".

Select "Record device" and click "OK" again.

Actually, here we select our USB flash drive, and just below we set the amount of memory available for recording.

You probably wondered what the choice of a flash drive is for if there is only one connector. Nobody forbids us to connect to the USB-hub connector, and to it there is already a USB flash drive, an external hard drive, and a card reader.

Three radios are a nice bonus:

disadvantages

1. No audio output
2. There is no built-in speaker, you will have to connect external speakers
3. Unable to connect computer

Advantages

1. Receiving digital TV
2. USB availability
3. HDMI availability
4. Availability of AV-out

In general, summing up, we can state a wide range of options. The version with an Android set-top box is suitable for those who want to make a TV out of a monitor for a kitchen or other room where there is access to the Internet. Two versions of the TV tuner for the monitor will suit those who do not want to depend on the Internet and have a very simple solution for watching TV on a monitor. The first version of the TV tuner is suitable for those who want to supplement their computer with the ability to watch TV, and the second option is suitable for those who just want to return a second life to the monitor and be able to receive digital TV.

Despite the fact that progress is striding by leaps and bounds, you should not throw away seemingly unnecessary, outdated things, as we can see they can serve you still, but in a slightly different quality. It is enough just to buy an additional device and a useless thing becomes not only useful, but also acquires an incredibly wide range of possibilities.

Modern electronics stores offer an extremely wide range of television equipment: from budget models to expensive new products. However, not every consumer can afford to buy a new TV.

What is the way out of this situation? Everything is very simple, convert the monitor into a TV, especially since it's really not difficult to do it. Firstly, today, probably, everyone has a computer monitor. Secondly, even if it is not there, then a new one is still much cheaper than a TV device.

How to make a TV from a monitor? There are several different ways... Everyone can customize the TV with their own hands, the main thing is to follow the instructions. In the future, it can even be used to receive cable channels.

Monitor as TV

It may seem to many that it is impossible to turn a monitor into a TV, but it is not. It will take some free time to implement this plan. Let's start with choosing a monitor - which one is most suitable for such functions?

Experts conducted extensive testing, checking the performance of a huge number of different monitors, we invite you to familiarize yourself with the results of the study in order to make an objective decision. The leading position is held by the popular South Korean manufacturer Samsung... Converting such a display into a TV is quite simple.

Second place was shared by Sony and LG, offering consumers updated screens with an exclusive design. You can use a computer monitor like a TV, regardless of the manufacturer.

When using a monitor as a TV, you need to consider such a parameter as screen resolution. Naturally, if it is high, then the image quality will be appropriate.

Perhaps the main difficulty for a beginner will still be the lack of special skills. For example, not everyone can solder a module or connect a component. To avoid mistakes, follow the instructions or seek professional help. The system unit is not needed, the main thing is that there is a screen and a power supply unit for it.

TV from an old CRT monitor

Cathode ray tube displays have lost their popularity with the advent of liquid crystals. However, few people sold or threw away the CRT monitors that were out of use, the prudent owners hid them, as they say "for later." Actually, today the moment has come when you can make a TV out of the old screen, breathing a second life into unnecessary equipment.

How to make a TV? We answer the main question, which is undoubtedly of interest to absolutely everyone. The easiest way is to remove the control unit and graphics card. You also need to purchase additional components, they can be found in any TV equipment store.

The main condition is the presence of a VGA connector, without this interface it is absolutely impossible to turn an old CRT monitor into a full-fledged TV device. However, all old screens were equipped with this port for connection. system unit PC.

If you know absolutely nothing about connection diagrams, basic computer components, then turn old monitor it is unlikely that it will work into the TV, certain skills and knowledge will still be required to achieve the set task.

The following components and components are needed for the product being created:

1. The most important functional device of television equipment is the module responsible for adjusting the color of the image. The quality of the broadcast picture depends on the correct operation of this node.

Color module from TV AIWA TV-1402KE

1. Radio channel - this module selects intermediate frequencies among all incoming signals, which is necessary for television broadcasting.

Radio channel modules 40-32V6GM-NIUI2XG

1. The control unit is a part responsible for setting up and controlling the TV in manual and remote modes.

Samsung TV control unit UE32F4500AKXKZ

To make a TV yourself, connect the missing nodes and insert them into the screen case, having previously connected them with loops with other base modules. It is possible that resistors will be needed to enhance the image quality; they need to be soldered. Then a comprehensive check is carried out.

LCD TV

The modern consumer is gradually abandoning the stationary PC. It is not surprising, because you can buy more compact and no less functional laptops, netbooks. Therefore, if you have left, then do not rush to throw it away or sell it, because you can make TV out of it.

Again, first you have to visit a store or the radio equipment market in order to acquire the nodes necessary for the implementation of this idea:

• splitter and cable for connecting digital television;

• antenna and cable for its connection.

To connect a new TV, you need at least 2 sockets - for the tuner and the power adapter. Connect antenna cable and plug in the plugs. On the back side, you need to attach the tuner and the power adapter.

The tuner is equipped with a built-in speaker, its sound will fully satisfy the needs of an ordinary user. Aesthetes and music lovers will have to additionally purchase an external speaker system to expand the sound range. What options? For example, you can take a soundbar or DK with a subwoofer, even ordinary speakers will do.

A TV set from an LCD monitor will perfectly catch channels, but TV broadcasting in HD quality will remain unavailable - perhaps this is the main drawback.

If we compare the image quality of liquid crystal and CRT displays, then the preponderance is on the side of the former.

How to make a TV with a high-quality picture from a monitor? When making a TV from a monitor, you must consider several important points, which largely determine the quality of the image:

• signal response time;
• viewing angle;
• illumination;
• depth of dark tones;
• contrast.

710 monitor LG, like LCD from other manufacturers, has a long response to the signal. The viewing angle is also very small. These are too significant disadvantages. The bottom line is that the broadcast image will be of high quality as long as you sit clearly in front of the screen, a slight tilt will cause black spots to appear, the picture will be distorted.

It is impossible to solve the problems associated with insufficient black depth, which is why LCD monitors have lost the competition to LED displays.

In most cases, tuners are connected to the TV via the VGA connector. However, if the required interface is not available, you can always use an adapter adapter.

The goal of this project is to create a sun-lit display that can be installed on your window.
By creating a device, you get an energy efficient display without a backlight and an inverter.
It's nice to look out the window overlooking your garden, and in the left corner of the window you can see the time, current weather and weather forecast.

For this project we need:

Old computer LCD monitor (see next step);
Laptop, laptop, or Personal Computer based on windows OS (or in my case a simple client that connects to virtual machine on the server for improved energy efficiency);
VGA cable of sufficient length;
Glue gun;
Optional: Warm-up transparent glue cartridges.

Step 1: LCD panel requirements

There are some requirements for choosing an LCD panel.
As shown in the image above, the top images are the LCD panel with no ribbon cable running behind it.
Some panels, shown in the image below, have a flat cable that runs from the input PCB (top board) to the output PCB (board on the side of the panel). These panels CANNOT be used in this project, as the cable will be visible and visible when illuminated by sunlight. Only panels with two separate boards will do (top image).

Step 2: disassembling the monitor

At this step, you must completely disassemble the monitor.
It is necessary to take out almost everything.

Here is a list of the components to keep:
LCD panel (tinted glass like a panel with a printed circuit board attached to it);
Control board (if you can remove the board with the inverter, then take it out);
Flat cable between control board and LCD panel.
!!! BE EXTREMELY CAREFUL WHEN HANDLING THE LCD PANEL, IT IS VERY FRAGILE !!!
!!! YOU CAN EASILY TORK THE FLAT PANEL CABLE !!!

Step 3: attach to the window

Use hot glue to fix the LCD panel to the window.
This adhesive will provide excellent and secure fixing of the panel to the window.

I pinned my panel on September 1st, 2015 and it is now on January 18th, 2016. It has now been four months without any work done to reattach or adjust the position of the panel.

Step 4: fixing the LCD control board

The control board is also glued to the ceiling.
It adheres perfectly to wallpaper and does not come off over time.

Step 5: cable routing

Route the cables from the control board to the computer.
It is necessary to extend the power cable of the control board.
You can cut the power cable and take a longer piece of cable, then strip it and solder them together.

Step 6: software

This project requires:
Browser Google chrome https://www.google.com/chrome/browser/desktop
Currently (chrome extension) https://chrome.google.com/webstore/detail/currentl...
Auto Refresh (chrome extension) https://chrome.google.com/webstore/detail/auto-ref...

Install first chrome browser.
Then install the extensions using the footnotes above.
Typically, if you close and reopen your chrome browser, you will see the Currently (current time and weather) page.
If not, then open a new tab.

Then configure the Currently page by clicking on the three bars in the upper left corner.
We recommend using light colors for maximum visibility and setting the zoom value to “zoomed in” for better readability.
Install automatic update pages every 15 minutes (normal interval for weather updates).

The job is done, brains!
Now you can enjoy the display in your window :).

Step 7: Known Issue

If the panel is attached for a long period of time, bugs may appear between it and the window. Perhaps the reason for their appearance lies in the small amount of heat emitted by the panel. If the bugs start to annoy you, then remove the panel using a hair dryer or heat gun at the lowest setting, clean it, and then put the panel back.
In the end, the bugs are not visible at a distance of one and a half meters from the panel.

Step 8: end result

This video demonstrates the operation of the device on the first day after installation.

Good luck with your new brain projects!

In order to fix an LCD monitor with your own hands, you must first understand what the main electronic components and blocks consist of. this device and what each element is responsible for electronic circuit... Novice radio mechanics at the beginning of their practice believe that success in the repair of any device lies in the presence of a schematic diagram of a particular device. But in fact, this is a misconception and circuit diagram not always needed.

So, let's open the lid of the first LCD monitor that comes to hand and in practice we will understand its device.

LCD monitor. Basic functional blocks.

An LCD monitor consists of several functional blocks, namely:

LCD panel

The liquid crystal panel is a complete device. As a rule, the assembly of the LCD panel is carried out by a specific manufacturer, which, in addition to the liquid crystal matrix itself, integrates fluorescent backlight lamps, frosted glass, polarizing color filters and an electronic board of decoders into the LCD panel. digital signals RGB voltages for driving the gates of thin film transistors (TFT).

Consider the composition of the LCD panel computer monitor ACER AL1716... The LCD panel is a complete functional device and, as a rule, it is not necessary to disassemble it during repairs, except for replacing the failed backlight lamps.

LCD Panel Marking: CHUNGHWA CLAA170EA

On the back of the LCD panel is a fairly large printed circuit board to which a multi-pin ribbon cable is connected from the main control board. The PCB itself is hidden under a metal strip.

Acer AL1716 Computer Monitor LCD Panel

The printed circuit board contains a multi-pin NT7168F-00010 microcircuit. This microcircuit is connected to a TFT matrix and participates in the formation of an image on the display. From the NT7168F-00010 microcircuit, many pins depart, which are formed into ten loops under the designation S1-S10. These cables are quite thin and seem to be glued to the printed circuit board on which the NT7168F microcircuit is located.

LCD panel PCB and its components

Control board

The control board is also called the main board ( Main board). The main board contains two microprocessors. One of them is a control 8-bit SM5964 microcontroller with an 8052 core and 64 KB of programmable Flash memory.

The SM5964 microprocessor performs a fairly small number of functions. A button panel and an indicator of the monitor's operation are connected to it. This processor controls monitor on / off, start of backlight inverter. To save user settings, a memory chip is connected to the microcontroller via the I 2 C bus. Usually, these are eight-pin series non-volatile memory chips 24LCxx.

Main board of the LCD monitor

The second microprocessor on the control board is the so-called monitor scaler (LCD controller) TSU16AK... This microcircuit has many tasks. It performs most of the functions related to the conversion and processing of an analog video signal and preparing it for delivery to the LCD panel.

With regard to a liquid crystal monitor, you need to understand that it is inherently a digital device, in which all control of the pixels of the LCD takes place in digital form... The signal coming from the video card of the computer is analog and for its correct display on the LCD matrix it is necessary to make many transformations. For this, a graphic controller is intended, but in another way a monitor scaler or an LCD controller.

The tasks of the LCD controller include such as recalculation (scaling) of the image for various resolutions, formation of the OSD menu, processing of analog RGB signals and sync pulses. In the controller, analog RGB signals are converted to digital by means of 3-channel 8-bit ADCs that operate at 80 MHz.

The TSU16AK monitor scaler communicates with the SM5964 control microcontroller via a digital bus. For the operation of the LCD panel, the graphics controller generates synchronization signals, clock frequency and matrix initialization signals.

The TSU16AK microcontroller is connected via a ribbon cable to the NT7168F-00010 microcircuit on the LCD panel board.

If the graphics controller malfunctions, the monitor usually has defects associated with the correct display of the picture on the display (stripes may appear on the screen, etc.). In some cases, the defect can be eliminated by soldering the scaler leads. This is especially true for monitors that work around the clock in harsh conditions.

With prolonged operation, heating occurs, which has a bad effect on the quality of the soldering. This can lead to malfunctions. Defects related to the quality of soldering are not uncommon and are also found in other devices, for example, DVD players... The cause of the malfunction is degradation or poor-quality soldering of multi-pin planar microcircuits.

Power supply and backlight inverter

The most interesting in terms of study is the monitor power supply, since the purpose of the elements and circuitry are easier to understand. In addition, according to the statistics of malfunctioning power supplies, especially switching ones, they occupy a leading position among all the others. Therefore, practical knowledge of the device, element base and circuitry of power supplies will certainly be useful in the practice of repairing radio equipment.

The LCD monitor power supply consists of two. The first one is AC / DC adapter or in another way a network switching power supply (impulse). Second - DC / AC inverter ... In fact, these are two converters. AC / DC adapter is used to convert AC mains voltage 220 V into small DC voltage. Typically, voltages from 3.3 to 12 volts are generated at the output of a switching power supply.

The DC / AC inverter converts direct voltage (DC) into alternating voltage (AC) with a value of about 600 - 700 V and a frequency of about 50 kHz. An alternating voltage is applied to the electrodes of the fluorescent lamps built into the LCD panel.

Let's look at the AC / DC adapter first. Most switching power supplies are built on the basis of specialized controller microcircuits (with the exception of cheap chargers for mobile devices, for example).

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

Here are some examples of schematic diagrams of power supplies based on the TOP242-249 series microcircuits.

Fig 1: Example of a schematic diagram of a power supply

V following scheme dual diodes with a Schottky barrier (MBR20100) are used. Similar diode assemblies (SRF5-04) are used in the Acer AL1716 monitor unit we are considering.

Fig 2. Schematic diagram of a power supply unit based on a microcircuit from the TOP242-249 series

Note that the schematic diagrams shown are examples. Real schemes pulse blocks may differ slightly.

The TOP245Y microcircuit is a complete functional device, in the case of which there is a PWM controller and a powerful field-effect transistor, which switches with a huge frequency from tens to hundreds of kilohertz. Hence the name - switching power supply.

LCD monitor power supply (AC / DC adapter)

The scheme of operation of a switching power supply unit is as follows:

Rectification of alternating mains voltage 220V.

This operation is performed by a diode bridge and a filter capacitor. After rectification on the capacitor, the voltage is slightly higher than the mains voltage. The photo shows a diode bridge, and next to it is a filtering electrolytic capacitor (82 μF 450 V) - a blue barrel.

Converting voltage and lowering it using a transformer.

Switching with a frequency of several tens - hundreds of kilohertz DC voltage (> 220 V) through the winding of a high-frequency pulse transformer. This operation is performed by the TOP245Y microcircuit. A pulse transformer serves the same role as a transformer in conventional network adapters, with one exception. He works for more high frequencies, many times more than 50 hertz.

Therefore, for the manufacture of its windings, fewer turns are required, and, therefore, copper. But a ferrite core is needed, not transformer steel like 50 hertz transformers. Those who do not know what a transformer is and why it is used, first read the article about the transformer.

As a result, the transformer is very compact. It is also worth noting that switching power supplies are very economical, they have high efficiency.

Rectification of AC voltage reduced by a transformer.

This function is performed by powerful rectifier diodes. In this case, diode assemblies with the SRF5-04 marking are used.

To rectify high-frequency currents, Schottky diodes and conventional power diodes with a p-n junction are used. Conventional low-frequency diodes for rectifying high-frequency currents are less preferable, but are used for rectifying high voltages (20 - 50 volts). This must be taken into account when replacing defective diodes.

Schottky diodes have some features to be aware of. Firstly, these diodes have a low junction capacitance and are able to quickly switch - go from open to closed state. This property is also used to work at high frequencies. Schottky diodes have a small voltage drop of about 0.2-0.4 volts, versus 0.6 - 0.7 volts for conventional diodes. This property increases their efficiency.

Schottky barrier diodes also have undesirable properties that hinder their wider use in electronics. They are very sensitive to excess reverse voltage. When the reverse voltage is exceeded, the Schottky diode is irreversibly damaged.

A conventional diode goes into a reversible breakdown mode and can recover after exceeding the permissible reverse voltage value. It is this circumstance that is the Achilles heel, which causes burnout of Schottky diodes in rectifier circuits of all kinds pulse blocks nutrition. This should be taken into account when carrying out diagnostics and repairs.

To eliminate voltage surges that are dangerous for Schottky diodes, which are formed in the transformer windings at the pulse fronts, so-called damping circuits are used. In the diagram it is designated as R15C14 (see Figure 1).

When analyzing the circuitry of the power supply unit for the Acer AL1716 LCD monitor, damping circuits were also found on the printed circuit board, consisting of a 10 ohm smd resistor (R802, R806) and a capacitor (C802, C811). They protect Schottky diodes (D803, D805).

Damping circuits on the power supply board

It is also worth noting that Schottky diodes are used in low-voltage circuits with reverse voltage, limited to a few tens of volts. Therefore, if it is required to obtain a voltage of several tens of volts (20-50), then diodes based on p-n junction... This can be seen if you look at the datasheet for the TOP245 chip, which shows several typical power supply circuits with different output voltages (3.3 V; 5 V; 12 V; 19 V; 48 V).

Schottky diodes are sensitive to overheating. In this regard, they are usually installed on an aluminum radiator to remove heat.

Distinguish the diode on p-n basis the transition from the diode on the Schottky barrier is possible according to the conventional graphic designation in the diagram.

Schottky barrier diode symbol.

After the rectifier diodes, electrolytic capacitors are installed to smooth out voltage ripples. Further, using the obtained voltages 12 V; 5V; All units of the LCD monitor are powered by 3.3V.

DC / AC inverter

By its purpose, the inverter is similar to electronic control gear (ECG), which are widely used in lighting technology to power household lighting fluorescent lamps. But, there are significant differences between the electronic ballast and the LCD monitor inverter.

An LCD monitor inverter is usually built on a specialized microcircuit, which expands the range of functions and improves reliability. For example, the Acer AL1716 LCD backlight inverter is based on a PWM controller. OZ9910G... The controller microcircuit is mounted on a printed circuit board by planar mounting.

The inverter converts a constant voltage, the value of which is 12 volts (depending on the circuitry) into an alternating voltage of 600-700 volts and a frequency of 50 kHz.

The inverter controller is capable of changing the brightness of the fluorescent lamps. The signals for changing the brightness of the lamps come from the LCD controller. Field-effect transistors or their assemblies are connected to the controller microcircuit. In this case, two assemblies of complementary field-effect transistors are connected to the OZ9910G controller AP4501SD(Only 4501S is indicated on the body of the microcircuit).

Assembly of field-effect transistors AP4501SD and its pinout

Also, two high-frequency transformers are installed on the power supply board, which serve to increase the alternating voltage and supply it to the electrodes of the fluorescent lamps. In addition to the main elements, all kinds of radio elements are installed on the board, which serve to protect against short circuits and lamp malfunctions.

Information on repairing LCD monitors can be found in specialized repair magazines. So, for example, in the magazine "Repair and service of electronic equipment" No. 1 2005 (pp. 35 - 40), the device and the schematic diagram of the LCD monitor "Rover Scan Optima 153" are described in detail.

Among the malfunctions of monitors, there are quite often those that are easy to fix with your own hands in a few minutes. For example, the aforementioned Acer AL1716 LCD monitor came to the repair table due to a broken contact of the outlet for connecting the power cord. As a result, the monitor turned off spontaneously.

After disassembling the LCD monitor, it was discovered that a powerful spark was formed at the site of the poor contact, traces of which can be easily found on the printed circuit board of the power supply. A powerful spark was also formed because at the moment of contact, the electrolytic capacitor in the rectifier filter is charged. The cause of the malfunction is the degradation of the soldering.

Soldering degradation causing monitor malfunction

It is also worth noting that sometimes the breakdown of the diodes of the rectifier diode bridge can serve as the cause of the malfunction.

Here are the TOP 10 most common LCD monitor malfunctions that I experienced the hard way. The rating of faults was compiled according to the personal opinion of the author, based on the experience of work in 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 blink. In this case, the monitor lights up for a second and goes out, turns on and turns off immediately. 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, disassembling an LCD monitor is not difficult, but you need to remember about safety precautions.

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.

2nd place - the image blinks or goes out

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 flashing image on the monitor tells us that the monitor backlight voltage source is constantly jumping off the operating mode.

3rd place - spontaneously turns off

after the time has elapsed or does not turn on immediately. In this case, again, three frequent LCD monitors malfunctions 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.

4th place - no backlight,

but the image is viewed under bright light. This immediately tells us about the 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 generating 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 die to get to the end of the lamp and solder the high voltage wires.

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 ...

6th place - spots or horizontal stripes

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. Restore defective pixels monitor, alas, will not work.

7th place - no image, but backlight is present

That is, there is a white or gray screen on the face. First, 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. You need to check with a voltmeter if everything is in order with them.

If everything is in order, then take a close 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 outline 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 is easier to start up for spare parts, especially if you have a familiar karate fighter fighting against objectionable LCD monitors.

8th place - does not respond to control buttons

This case is easily treated - you need to remove the frame or back cover 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.

9th place - reduced monitor brightness

This is due to aging of the backlight lamps. LED lights according to my data does not suffer from this. It is also possible that the parameters of the inverter deteriorate, again due to aging of the constituent components.

10th place - noise, moire and image jitter

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 concludes my wonderful 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 and in the comments.

Best regards, Solder Master.

P.S.: How to disassemble a monitor and TV (how to snap off the frame)

Most FAQ 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.

P.P.S .: Power supplies and frequent malfunctions of LCD monitors

V recent times monitor manufacturers are increasingly equipping 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.

DIY LCD monitor repair

A common malfunction is a situation when the LCD monitor lights up for a second and goes out. What to do in this case and how to use this TOP of faults.

It's simple. To repair the LCD monitor, follow these steps:

• Step 1. Disconnect the monitor from the 220 V network and from the computer and decide - we will repair it ourselves or take it to the service for diagnostics at a low cost.
• Step 2. If you decide to figure it out yourself, then take the tools: screwdrivers, a knife or scalpel and a soft base to lay the monitor down with the matrix.
• Step 3. Disassemble the LCD display, observing safety precautions and remembering the latches. How they open is shown in the animation above.
• Step 4. Discharge the high voltage capacitor. It is necessary! Especially if you want to reach a positive result of the repair.
• Step 5. Inspect the board for swollen capacitors, burnt out transistors and microcracks.
• Step 6. In case of any finds at Step 5, replace the burnt one, solder the cracked one.
• Step 7. Check the performance of the monitor, observing safety precautions. If everything is in order, then go to Step 10.
• Step 8. Take a multimeter and ring the fuses, diode bridge, transformers and transistors. Replace burnt radioelements.
• Step 9. Check the operation of the LCD monitor. If the monitor continues to blink, then check the voltage at the test points on the board. This requires knowledge of circuitry, as well as a service manual with a circuit, ideally. Further actions are difficult to describe in general terms. This is where the creative process of the Renovator begins. For discussion, write in the comments or contact.
• Step 10. In case of a successful DIY repair of a flashing LCD monitor, do a test run for 2-3 hours in a disassembled state. The monitor can then be assembled and operated.