Do-it-yourself mystery car radio repair

It is not uncommon for the owners of car radios and CD / MP3-receivers to encounter cases of breakdown of their devices.

The reason for the damage to an expensive device can be an ordinary polarity reversal of the power wires of the car radio when connected, short-term voltage surges in the vehicle's electrical system, or wear and short circuit to the case of wires and cables.

It will tell you about car CD / MP3 player repair. Mystery MCD-795MPU... This manual will help with self-repair of car radios: cassette, disc (CD / MP3), discless (with USB). Basic knowledge of electronics will be enough for even a novice radio amateur to make this repair.

The car radio does not turn on, the fuse in the power circuit is blown.

As a rule, all car radios are equipped with a fuse in the positive 12V supply circuit. Fuse rating 10A. It is this fuse that burns out if an error is made when connecting the power wires of the car radio to the on-board network of the car (confused + and –).

There is one simple rule to keep in mind. If the fuse is blown, then you should not rush to install a replacement or "bug" (a simple piece of copper wire). The fact is that in most cases the fuse blows out after any element of the circuit has failed.

First you need to figure out the reason for the blown fuse. And if you install a new fuse, then there is a risk of "burning out" the car radio.

A fuse is the last line of defense when something has already "burned out" and consumes a huge current. It only serves to prevent overheating and fire of the connecting wires and cables.

So, let's analyze the car radio repair step by step Mystery MCD-795 MPU... The first step is to open the metal cover on the PCB side. Next, we inspect the printed circuit board for the presence of charred tracks, burnt parts. Sometimes burned-out paths cannot be detected with a cursory examination. For example, a break can be hidden under the main connector. This can be the case if the printed circuit board is double-sided.

The photo shows the location of the burnout of the printed track on the board.

Most likely, the owner of the device decided not to "steam" and connected the power directly, without a fuse, or put a "bug" trying to bring the car radio to his senses. This led to the fact that the printed track served as a kind of fuse and burned out as soon as a short-circuit current passed through it. In some cases, the whole is on, both the fuse and the printed tracks on the board.

Recovering a burned-out printed track.

To get to the radio components, we open the top metal cover, unscrew the 4 screws securing the CD / MP3 deck.

We take out the disk deck without forgetting to unfasten the 2 cables connected to the main board. Usually, cables and connectors are detached quite easily, no additional tools are required.

Next, we find the protective diode on the board. It is usually located closer to the supply circuits and the main connector.

It is necessary to evaporate it and check for “breakdown”. On "breakdown" - it means to measure its resistance in direct and reverse connection. The diode has one-sided conductivity. If it “rings” like an ordinary copper wire, then it is punctured. I talked about checking semiconductor diodes with a digital multimeter here.

Since the diode is “clamped” by the filter choke, we had to first evaporate it.

We change the probes of the multimeter in places, as in the photo.

As you can see, the multimeter shows zero resistance in both directions - the diode is broken.

We look at the brand of the diode - 1N5401... It is necessary to select an analogue for it and replace it with a serviceable one. Diodes of the 1N5400-1N5408 series are designed for an average forward current of 3 amperes. Any rectifier diode of this series or any other for a current of 3 amperes will do. Full documentation (datasheet) for diodes of the 1N5400-1N5408 series can be viewed on the website or search through Internet search engines.

If a suitable diode is not at hand, you can take the same one from a non-working car radio, which was done. The protective diode 1N5402 dropped out of the non-working board of the cassette recorder.

Before soldering a borrowed, used diode, be sure to check it.

If you can't find a suitable diode in any way, then you can not solder it at all, but only evaporate faulty!

The essence of this diode is that during the normal operation of the car radio, it is constantly closed and does not pass current, so to speak, "idle". It is turned on in the opposite direction to the 12V power supplied to the car radio. As soon as the polarity of the voltage changes to the opposite (if connected incorrectly), the diode will begin to pass current through itself. Since there is no load in the diode circuit, a very large short-circuit current will flow through it. It will blow the fuse. Almost always, along with the fuse, the printed tracks on the board burn out, and sometimes the diode itself.

This is the protective role of the diode, which takes the entire blow on itself, preventing the failure of the amplifier microcircuit and other units of the car radio. Therefore, you do not need to replace it. The car radio will work properly. But in the event of a repeated polarity reversal of the power supply, other elements of the circuit can also burn out, for example, an audio frequency power amplifier (UMZCH) microcircuit, which is quite expensive.

It also happens that due to long-term operation or manufacturing defects, it is just the protective diode that fails. Naturally, there is no malfunction of the car's on-board network.

Before connecting the repaired car radio to the vehicle's electrical system, you should make sure that the wiring is in good condition and that the standard voltage is present, otherwise you can “burn” it again.

Aradio is a very common electronic device. With rare exceptions, this undoubtedly useful device is not present in the car. The evolution of car radios is the video recorder and the car CD / MP3 player. But despite changing the recording medium in a car player, these devices are still referred to by the familiar word. car radio... It has been well established since the massive use of car cassette players.

Danny the section of the site is devoted to the issues of repairing car radios with your own hands. It's no secret that car players of various modifications and manufacturers break down.

Non the pages This section will not be a simple listing of specific malfunctions of certain car radio models, but methods of repair and restoration of these devices will be revealed. The presentation will be conducted without interrupting practice, with examples of repairing specific models of car turntables.

Introduction article. It describes the necessary devices that will be required in the process of repairing car radios.

How to connect a car radio or car CD / MP3 receiver to a computer power supply (PSU)? Anyone who wants to "power" a car radio from a 220V network faces this question. This makes sense if you plan to repair the car radio or upgrade it to a stationary music center.

Here you will learn about typical car player malfunctions and their causes.

What is a complex malfunction and how can error codes help in car radio repair? A real example of troubleshooting a complex malfunction of the Pioneer DEH-P3500MP car CD receiver.

When repairing disc car radios, it is often necessary to disassemble the CD mechanism. Shown in detail is the method of disassembling the CD mechanism, which is widespread among modern car CD / MP3 players.

CD drives for car receivers of different brands differ in their design. This means that you need to be able to disassemble CD mechanisms of different types. Here you will learn how to disassemble the CD drive of the Kenwood car radio without errors.

An article that tells about one of the typical malfunctions of car CD / MP3-receivers - there is no display backlight. How to fix this breakdown will be discussed.

Here we talk about an atypical breakdown of the Mystery MCD-778MP car CD / MP3 receiver. A real example of repair using an oscilloscope.

The volume control of the car radio does not work? The knob may be the cause of the problem. The rotary encoder is very often used in digital equipment to adjust various functions and control the device. Is it really necessary to replace the rotary encoder if it does not work correctly? How to restore the correct operation of the knob and avoid replacing it is described in this article.

In the practice of repairing car players and CD-receivers, there are cases when a schematic diagram, information on the pinout of the connector or a table for decoding error codes is needed. This information is contained in the service manual for a specific car radio model. You can download the service manual for some models of popular car radios by clicking on the link above.

Which brand of car radio should you choose? Read this article and this question will disappear forever.

Find out about the device of SD / MP3 car receivers. Among all kinds of modifications of car radios, so-called flash car radios have found their place under the sun. This article examines the device and the elemental composition of car SD / MP3-receivers without a disk using the example of the Velas V-201U model.

The car radio, like any other device or mechanism in the car, can fail. As practice shows, the repair of car radios is usually carried out in the event of improper operation of the device or in the event of malfunctions not related to use. In this article, we suggest that you familiarize yourself with the main causes and methods of eliminating audio system breakdowns.

It's no secret that over time, the mechanical elements of a multimedia system tend to wear out. So, if the system does not turn on or off, it is necessary to either repair or replace it.

But first, let's figure out the main reasons why the radio tape recorder does not work:

1. Dirty device. If the radio tape recorder stops working, this may be due to contamination of the mechanisms - dirt or dust can accumulate between them, especially if the system is used in harsh conditions. As a rule, optical or mechanical components break in this case. One of the signs of contamination is a disc that is stuck and cannot play properly.
2. Also, mechanical failures can be the reason. This type of failure is usually associated with the power circuit. If the connection of the head unit was made incorrectly initially, or the electrical circuit is characterized by sharp drops, then there is nothing to be surprised at. The first symptom of problems with the power circuit is the lack of screen backlighting or the inability to start the radio.

Car audio system board

Before removing the radio from the car and starting to repair it, read the list of faults specific to audio systems.Getting and repairing the car radio from the car is not such a problem, but before you pull it out, you need to know exactly what to repair.

1. Perhaps the problem is the lack of power at +5. If you decide to get the device and repair it yourself, first of all you need to pay attention to diagnostics of the second contact of the CN701 connector. It should have a voltage in positive territory of 14 volts, this voltage should be transmitted to the collectors of the transistors. If there is no voltage, repairing car radios consists in replacing transistors or a zener diode.
2. There is no power activation signal. Before repairing car radios, you need to check the voltage of + 4.8 volts at the fortieth contact of the IZ901 controller. You should also check for a pulse on the third contact of the controller.

Dialing a multimedia system with a multimeter

Repair of car radios on your own or by a specialist is required if there is no sound volume or when the volume is increased and the tracks are played, the sound fills.

There may be several options:

Why does the radio tape recorder not read a USB flash drive or disc after starting the engine? The disk is stuck, stutters, the system does not see the USB flash drive?

The reasons may be as follows:

1. The radio tape recorder does not read the USB flash drive, does not see the disc, or the disc stutters or is stuck after starting the engine. Perhaps the device simply does not understand the recording format. Repair of radio tape recorders in this case is not required, you just need to burn the disc in a different format.
2. If the system does not see the disc when starting the engine, the disc is stuck, stutters or heats up, this may be due to contamination of the optical lens. As mentioned above, problems in the operation of buttons and the device as a whole after starting the engine can be associated with dirt. In this case, the problem is solved by using a special cleaning disc. The operation of such a disk is carried out in accordance with the requirements specified in the instructions. You can self-clean the system by blowing the elements or cleaning with a cotton swab.
3. Another reason may be the lack of laser current; you can get rid of such a malfunction by adjusting it.
4. Inoperability of loops and wires. Perhaps, during the operation of the car, the screws inside the structure simply loosened, or it could be a leakage of resistors.

Buttons do not work - there are several reasons. First, it may be mechanical damage to the buttons. To restore the functionality of the buttons, you need to disassemble the front panel and check the condition of the contacts. Perhaps the contacts from the buttons simply leave and they need to be re-soldered. If the button is inoperative, then it will have to be changed.

Secondly, the problem with the buttons may be due to a software malfunction. The malfunction is solved by rebooting the audio system and returning its functionality to the factory configuration. All settings will be erased from memory. After returning to factory settings, the device must be turned off for a few minutes.

If the radio tape recorder heats up and turns off arbitrarily, there may be several reasons:

1. The system heats up and shuts down as a result of poor power supply. Lack of power will cause the radio to turn off arbitrarily, or this is due to power failures. When the radio tape recorder heats up and turns off, you need to check the power cable - it may just come off or break, then it will have to be changed.
2. The device heats up due to poor ventilation and turns off when overheated. If the system heats up, this indicates insufficient ventilation. Such a malfunction is relevant for Pioneer radio tape recorders and, as car owners of such systems assure, there is nothing to worry about. But if the system heats up constantly and turns off at the same time, you need to think about additional ventilation.
3. Sometimes the device turns off due to software glitch. You can try to solve such a malfunction by resetting the radio to factory settings.

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Is your TV, radio, mobile phone or kettle broken? And you want to create a new topic about this in this forum?

First of all, think about this: imagine that your father / son / brother has an appendicitis pain and you know from the symptoms that it is just appendicitis, but there is no experience of cutting it out, as well as the tool. And you turn on your computer, access the Internet on a medical site with the question: "Help to cut out appendicitis." Do you understand the absurdity of the whole situation? Even if they answer you, it is worth considering factors such as the patient's diabetes, allergies to anesthesia and other medical nuances. I think no one does this in real life and will risk trusting the life of their loved ones with advice from the Internet.

The same is in the repair of radio equipment, although of course these are all the material benefits of modern civilization and in case of unsuccessful repairs, you can always buy a new LCD TV, cell phone, iPAD or computer. And for the repair of such equipment, at least it is necessary to have the appropriate measuring (oscilloscope, multimeter, generator, etc.) and soldering equipment (hairdryer, SMD-hot tweezers, etc.), a schematic diagram, not to mention the necessary knowledge and repair experience.

Let's consider the situation if you are a beginner / advanced radio amateur who solders all sorts of electronic gizmos and has some of the necessary tools. You create an appropriate thread on the repair forum with a short description of “patient symptoms”, ie. for example “Samsung LE40R81B TV does not turn on”. So what? Yes, there can be a lot of reasons for not switching on - from malfunctions in the power system, problems with the processor or flashing firmware in the EEPROM memory.
More advanced users can find the blackened element on the board and attach a photo to the post. However, keep in mind that you replace this radio element with the same one - it is not a fact that your equipment will work. As a rule, something caused the combustion of this element and it could “pull” a couple of other elements along with it, not to mention the fact that it is quite difficult for a non-professional to find a burned-out m / s. Plus, in modern equipment, SMD radio elements are almost universally used, soldering which with an ESPN-40 soldering iron or a Chinese 60-Watt soldering iron you risk overheating the board, peeling tracks, etc. The subsequent restoration of which will be very, very problematic.

The purpose of this post is not any PR of repair shops, but I want to convey to you that sometimes self-repair can be more expensive than taking it to a professional workshop. Although, of course, this is your money and what is better or more risky is up to you.

If you nevertheless decide that you are able to independently repair the radio equipment, then when creating a post, be sure to indicate the full name of the device, modification, year of manufacture, country of origin and other detailed information. If there is a diagram, then attach it to the post or give a link to the source. Write down how long the symptoms have been manifesting, whether there were surges in the supply voltage network, whether there was a repair before that, what was done, what was checked, voltage measurements, oscillograms, etc. From a photo of a motherboard, as a rule, there is little sense, from a photo of a motherboard taken on a mobile phone there is no sense at all. Telepaths live in other forums.
Before creating a post, be sure to use the search on the forum and on the Internet. Read the relevant topics in the subsections, perhaps your problem is typical and has already been discussed. Be sure to read the article Repair strategy

The format of your post should be as follows:

Topics with the title “Help fix the Sony TV” with the content “broken” and a couple of blurred photos of the unscrewed back cover, taken with the 7th iPhone, at night, with a resolution of 8000x6000 pixels are immediately deleted. The more information about the breakdown you put in a post, the more chances you will get a competent answer.Understand that the forum is a system of gratuitous mutual assistance in solving problems and if you are dismissive of writing your post and do not follow the above tips, then the answers to it will be appropriate, if anyone wants to answer at all. Also note that no one should answer instantly or within a day, say, no need to write after 2 hours “That no one can help”, etc. In this case, the topic will be deleted immediately.
You should make every effort to find a breakdown on your own before you get stuck and decide to go to the forum. If you outline the whole process of finding a breakdown in your topic, then the chance of getting help from a highly qualified specialist will be very great.

If you decide to take your broken equipment to the nearest workshop, but do not know where, then perhaps our online cartographic service will help you: workshops on the map (on the left, press all buttons except “Workshops”). You can leave and view user reviews for workshops.

For repairmen and workshops: you can add your services to the map. Find your object on the map from the satellite and click on it with the left mouse button. In the field “Object type:” do not forget to change to “Equipment repair”. Adding is absolutely free! All objects are checked and moderated. A discussion of the service is here.

A car player, the main purpose of which is initially high-quality reproduction of music records from a tape cassette, CD-disk or flash card during a trip or a long wait (in traffic jams), very often upset its users with the following breakdowns:

• lack of sound;
• poor sound quality. wheezing, squeaking and so on;
• refusal to play records from cd, mp3-disks.

How to disassemble?

That is, for the most part, in violation of their direct duties. We will tell you in more detail what to do if sound disappeared on your car radio (Mystery, Pioneer).

The display lights up and gives information that the CD (flash drive) is being read, but there is no sound. Often this situation occurs with the following breakdowns:

• disruption of power supply circuits;
• failure of the speakers (speakers) of the car;
• amplifier malfunction;
• violation of contacts (solder) of the device;
• closure of the electrical circuit;
• the use of a powerful acoustic system that exceeds the technical capabilities of the radio.

The first, the main method that should be used in the event that your sound-reproducing equipment has lost sound is to ask for help from a specialist: to conduct a diagnostic examination of the device itself and its components in order to determine the cause of the breakdown and eliminate it in a specially designed technical center. You should not start doing self-repair if your device is under warranty service. Very often, the masters working on this profile, upon detecting external interference with the player, simply remove it from the warranty. This means that you will pay separately from your own pocket for equipment repairs.

In the case (second method), when the warranty period has already expired or it did not exist at all, you have the knowledge (initial), the necessary instruments and tools, confidence in your abilities, you should try to restore the device to work with your own hands.

Do-it-yourself repair of the Mystery radio tape recorder in case of suspicion of electrical circuit failure is carried out according to the following scheme.

With a multimeter, nickname the sections of the circuit in contact with the car radio for detecting a malfunction. As a rule, this can be a burnt out capacitor. We replace it with a new one. In the event that such a breakdown does not occur for the first time, we replace the capacitor with a more powerful part in terms of capacity.

Failure of both speakers is a rare occurrence. This usually happens to one of them.But then the sound does not disappear at all, but only worsens. If, nevertheless, both speakers are silent at the same time, use a tester to look for the cause in a broken contact with poor insulation, a short circuit, a malfunction of the power circuits or an amplifier breakdown is possible.

To repair the radio with your own hands, if the sound does not turn on, and more specifically, to replace the amplifier, you will need the following tools:

• soldering iron;
• solder;
• Screwdriver Set;
• tweezers;
• pliers;
• new amplifier board.

After preparing the named tools, we proceed to work in the following order:

• We disconnect the radio tape recorder from the on-board power supply after removing the device from the receiving socket.
• Remove the bottom and side covers of the device, the front panel.
• We release access to the replaceable amplifier board.
• With a preheated soldering iron, we soften the solder of the board.
• We very carefully straighten the bent ends of the latches holding the electronic board with pliers.
• We remove the board.
• Protecting the nearby parts and microcircuits with foil, carefully solder the worn-out board and remove it.
• We prepare the seat for the new part by removing the remnants of the solder and degreasing the seat with ethyl alcohol.
• We install a new board, if necessary, align its mounting legs with tweezers.
• We fix the part by soldering the legs.
• We check the correctness of the work performed with a multimeter for the absence of new damage that may occur due to careless handling with a soldering iron.
• We collect and install the car radio in its usual place.

Replacing the amplifier (board) is the most difficult and expensive DIY car player repair with complete or partial disappearance of the sound. The same faults as a violation of the integrity of solders and a short circuit of the electrical circuit are detected easily and quickly, and are corrected with a multimeter and a soldering iron.

As for the loss of sound after you install a more powerful speaker system in your car that exceeds the technical capabilities of the radio, just adjust their parameters, which are necessary for high-quality and full-fledged playback of sound files.

We consider it our duty to remind once again that any actions to repair the acoustics of a personal car (with the exception of frankly minor malfunctions) are best left to professionals, despite the high cost of this kind of work. If you make mistakes during the repair with your own hands, you can be left not only without sound, but also generally render the entire audio system unusable. Therefore, before starting, carefully study all the available information on fixing a breakdown, as well as photo and video materials related to this issue.

If you need to repair your Mystery car radio, the specialists of our service center will provide their services at the highest level at low prices. We install components and spare parts from trusted suppliers, providing an additional guarantee for performance. There is a service of free delivery of equipment to the workshop and back, as well as the possibility of urgent repairs.

I gave my car radio to this service. I bought a used car already together with Mystery MMTD 9122S. Everything worked, it just stopped listening to the radio and after searching on the Internet, I turned to this service center. I read the reviews, called the workshop, received advice and after preliminary agreement on the cost, a courier arrived. We replaced the antenna and it worked. The prices are affordable, the service is at a good level, everything is well organized!

The flash drive stopped reading on my Mystery car radio. I found this service on the Internet and left a request online. I liked the efficiency. Phoned me and sent a courier free of charge. After the diagnosis, they called back and offered the cost of the repair, which suited me. We changed the USB connector and gave a guarantee for work, provided documents. The courier brought it, I installed it, checked it and only then paid!

It's nice that there is a service center with such a level of service! The backlight on the panel display from the Mystery car radio stopped working. After diagnostics in this service center, my assumptions were confirmed - after a good shake-up, it was necessary to fix the loops. So the experts know their stuff. I recommend this workshop, the prices and the level are very decent!

MYSTERI MAR 909U (V5N10), repair without circuit diagram.

A mystery mar-818u car radio was in my hands. after connecting to the power supply, the device turned off when trying.

We wanted to buy a new radio tape recorder, but decided to fix the old one.

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I have been struggling with the socket from the tape recorder, not the first day, tell me who repaired and it kept after that - how.

The radio does not turn on. I disassemble and see if there is any external damage. A solder burst on the power connector.

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Car radio repair, amplifier microcircuit replacement.

The person confused plus and minus on the radio when connected. After reversed the polarity on.

Hello everyone. Guys, if your mafon is broken, you don't need to take it in for repair. You can fix it yourself.

mystery mtv 2428lt2, Mystery TV does not turn on, does not show signs of life, there is no indication. Troubleshooting.

Philips car radio repair, short circuit search, analog selection (tutorial, tips :)

Car radios from China are highly sought after electronic devices used by Russian drivers. Such devices are inexpensive, and the benefits are enormous.
In this regard, the repair of Chinese pioneer car radios is very relevant and the ability to do it yourself will become a truly excellent talent. In this article, we will learn how to repair a car radio with our own hands.
China has always been famous for its electronic technology and the number of manufactured products that have flooded the world markets. So there will be practically no problems with parts on the car radio.
Recently, car radios have experienced an unprecedented heyday and technological surge. Appliances such as videotapes and MP3 players have evolved.
Despite the change in media, we still call all devices a car radio, and this name has been firmly established since the days of using cassette equipment.
Unfortunately, Chinese Pioneer car radios are paying the price for their immense popularity by frequent appearances in repair shops. And it's not just the quality of the products, which, frankly, is inferior to the Japanese and European models, but in harsh operating conditions.
Constant vibration, dust, voltage instability - all this leads to equipment failure.

It is not difficult to carry out repairs at home, but you need to acquire several necessary components, so to speak, the necessary equipment.

First of all, the pioneer car radio needs to be supplied with power, because it does not have a built-in unit, as in music centers.
It is not recommended to use a battery for this purpose. We need a network power supply, which will become the most acceptable option.
Power supply requirements:

• The power supply must provide an output voltage of 12-13 V.
• The power supply must withstand a load of 10 amperes.

Note. Naturally, you can use a power supply with a lower load current, because a 10A standard radio tape recorder consumes at a very high volume, and during repairs, you do not need to increase the sound so much.

• You can also use a homemade power supply, but it must have a powerful transformer.
• You can use a PC power supply that has an AT or ATX format (such a switching power supply for a personal computer has several outputs with a voltage of 12V and 5V, and it is these voltages that will be needed for repairs).

A digital multimeter is a standard measuring instrument that a novice repairer should have. Such a multimeter will allow you to measure not only voltage, but current and resistance.
In addition, modern multimeters have other additional features.This is a kind of "eye" of the electronics engineer, allowing him to evaluate what is happening in the electronic circuit.

The standard set of electronic tools includes:

Malfunctions can be different and below are the most common "ailments" and how to treat them.

• In the first place in the list of typical malfunctions of Chinese Pioneer car radios, it is the inability to read CDs and malfunctions during playback. The reason lies, as a rule, in the CD-mechanism itself, where there are a large number of electromechanical and mechanical components.

• If the malfunction is mechanical, then the tiny electric motor in the CD drive is replaced.

Note. It also happens that the engine in the CD drive does not have obvious damaged mechanisms, but gives out understated revs. In this case, it will be much more difficult to find the faulty element.

It is an equally common reason for poor performance of the car radio. There is nothing surprising in this, because almost all car radios are operated in harsh conditions when the optics and mechanics are contaminated. If dust gets into the device, playback malfunctions, the car radio freezes or the disc does not load.
Solution:

• The CD drive is disassembled and the lens of the laser reader is cleaned. This is usually enough so that the deposited dust does not interfere with the laser beam focusing on the surface of the disk.

Note. During the repair process, do not forget about checking the operation of the car radio with different disc formats.

Another common reason. This problem appears when the supply voltage is incorrectly connected, or when voltage surges are observed in the vehicle's on-board network. In this case, the car sound system may not turn on at all, or the sound or display backlight may disappear.
Solution:

• The protective fuse is checked.
• The protective diode is checked.
• The printed circuit board is inspected for burned tracks and capacitors.
• The microcircuits are examined for damage to the case: chips, cracks, etc.

• UMCHZ - this is what this microcircuit is called, which is a component of an audio frequency power amplifier. Failure of the UMZCH, as a rule, is associated with incorrect connection of the speakers, or with a short circuit in the circuit. As a result, one of the amplification channels does not work, which affects the sound in one of the speakers.

Attention. When connecting the car radio, the power must be connected last, before making sure that everything is done correctly and the connections correspond to the manual.

• Failure of the UMZCH can also be associated with overvoltage. It is noteworthy that the supply voltage of this microcircuit is not stabilized by anything and tends to fluctuate within a certain permissible interval.

• The microcircuit is simply replaced with a new one.

• In its pure form, mechanical failure that occurs due to vibrations or shaking of the soldering. Over time, the connectors for connecting the car radio are destroyed, and on Chinese models they are generally made poorly.
  As a result, normal electrical contact is disrupted.
• Spontaneous shutdown of the car radio, loss of sound or its absence - this is only an incomplete list of violations that occur during soldering degradation.

• The quality of the soldering of the car radio connector is checked.

• With this malfunction, the car radio does not respond to user commands when buttons are pressed.
• The car radio may start to "glitch".

China car radio with a menu in Russian

• The removable panel is disassembled. The ohmmeter checks the operation of all buttons.

It is also a common cause of car radio malfunction. A knob is a volume control that either deteriorates over time (Chinese ones quickly fail) or gets dirty.
Solution:

• Simple cleaning of internal contacts from dirt and oxidation, after disassembling the knob.The regulator itself must be properly dismantled from the car radio using a special desoldering tool.
  You also need to disassemble without using unnecessary force.

Note. The rotary encoder is cleaned with a special spray that is easy to apply to surfaces and evaporates quickly.

• If it does not help, the knob is replaced with a new one.

• A common breakdown that most often affects Chinese car radio models. In the disc playback mode, the car radio does not show a malfunction, but during loading / unloading - problems.
  In a word, those nodes that are controlled by the driver itself do not work. At the same time, the driver microcircuit heats up a lot, reaching as much as 80 degrees Celsius.

Universal car radios from China

• We replace the driver by dismantling the faulty hot-air soldering iron. The installation of the new driver is carried out with a low-power soldering iron with a narrow tip for 25-40 watts.

The above were the most common malfunctions of Chinese-made car radios and instructions for repairing do-it-yourself car radios. In the process of repair, it will be useful to use photo and video materials.
The price of parts for Chinese car radios is very cheap, so there will be no large repair costs.