In detail: do-it-yourself auto amplifier repair from a real master for the site my.housecope.com.
Repair of UMZCH is almost the most frequent of the questions asked on amateur radio forums. And besides, it is one of the most difficult. Of course, there are “favorite” faults, but in principle, any of several tens, or even hundreds of components that make up the amplifier can fail. Moreover, there are a great many UMZCH schemes.
Of course, it is not possible to cover all the cases encountered in the repair practice, however, if you follow a certain algorithm, then in the overwhelming majority of cases it is possible to restore the device's operability in a completely acceptable time. This algorithm was developed by me from the experience of repairing about fifty different UMZCH, from the simplest, for a few watts or tens of watts, to concert "monsters" of 1 ... 2 kW per channel, most of which were sent for repairs without schematic diagrams. The main task of repairing any UMZCH is to localize the failed element, which entailed the inoperability of both the entire circuit and the failure of other stages. Since there are only 2 types of defects in electrical engineering: then the "super task" of the repair is to find the broken or broken element. And for this - to find the cascade where it is located. Further - "a matter of technology." As the doctors say: "The correct diagnosis is half of the treatment." The list of equipment and tools required (or at least highly desirable) during the repair: Consider this algorithm using the example of repairing a hypothetical transistor UMZCH with bipolar transistors in the output stages (Fig. 1), which is not too primitive, but also not very complicated. This scheme is the most common "classic of the genre". Functionally, it consists of the following blocks and nodes: We turn on the amplifier. The lamp should blink (while the filter capacitors are charging) and go out (a weak glow of the filament is allowed). This means that K.Z. on the primary winding of the network transformer there is no obvious short circuit. in its secondary windings. With a tester in the alternating voltage mode, we measure the voltage on the primary winding of the transformer and on the lamp. Their sum must be equal to the network.We measure the voltages on the secondary windings. They should be proportional to what is actually measured on the primary winding (relative to the nominal). You can turn off the lamp, put the fuse in place and turn on the amplifier directly to the network. We repeat the voltage check on the primary and secondary windings. The ratio (proportion) between them should be the same as when measured with a lamp. The lamp burns constantly at full incandescence, which means we have a short circuit. in the primary circuit: check the integrity of the insulation of the wires coming from the mains connector, power switch, fuse holder. We unsolder one of the reasons going to the primary winding of the transformer. The lamp went out - most likely the primary winding (or turn-to-turn circuit) is out of order. The lamp burns constantly in incomplete incandescence - most likely, a defect in the secondary windings or in the circuits connected to them. We unsolder one wire from the secondary windings to the rectifier (m). Do not confuse, Kulibin! So that later it would not be excruciatingly painful from improper soldering back (mark, for example, with pieces of adhesive masking tape). The lamp went out - it means that everything is in order with the transformer. It is lit - again we sigh heavily and either look for a replacement for it, or rewind. 6. It was determined that the transformer is in order, and the defect is in the rectifiers or filter capacitors. We call the diodes (it is advisable to unsolder under one wire going to their terminals, or to solder it out, if it is an integral bridge) with a tester in ohmmeter mode at the minimum limit. Digital testers often lie in this mode, so it is advisable to use a dial gauge. Personally, I have been using the “squeaker” dial tone for a long time (Fig. 2, 3). Diodes (bridge) are broken or broken - we change. Integers - we call the filter capacitors. Before measuring, they must be discharged (.) Through a 2-watt resistor with a resistance of about 100 ohms. Otherwise, you could burn the tester. If the capacitor is intact, when closed, the arrow first deviates to the maximum, and then rather slowly (as the capacitor is charged) "creeps" to the left. We change the connection of the probes. The arrow first goes off scale to the right (there is a charge on the capacitor from the previous measurement) and then creeps to the left again. If there is a capacitance meter and ESR meter, then it is highly desirable to use one. We replace broken or broken capacitors. Sun 6 Jul 2014 It's no secret that to get high-quality sound and powerful bass in a car, you definitely need a power amplifier. Today, fortunately, on the market you can find car amplifiers for every taste, it all depends on your specific needs. An amplifier for 200-400 watts is enough to power the standard car acoustics, but among us there are true connoisseurs of sound pressure, audiophiles and music lovers who will not be surprised by a couple of hundred watts of sound power. It is for such people that class D amplifiers were invented - digital audio amplifiers that have high efficiency, compact dimensions and many other advantages. Unfortunately, a car amplifier sometimes breaks down, in some cases repairs are more expensive than the initial cost of the amplifier itself, so it is very desirable to consider or try to repair it yourself, because sometimes a blown fuse can be the cause of a breakdown. Having at hand a simple and cheap multimeter with diode continuity mode, you can find most of the defects that are very often observed in many car amplifiers. Any car amplifier consists of three main parts - a voltage converter, a power amplifier block and a filter block (crossover). A voltage converter or inverter is the most vulnerable part in any amplifier - 90% of the problems are associated with this particular node. The converter essentially powers the entire amplifier including the filter bank. Exclusively all voltage converters are made according to a standard push-pull circuit using a PWM controller, most often on a TL494. Then everything is standard - driver, power transistors, transformer, rectifier and filter unit. In some (cheap) amplifiers, inverter circuits of an unregulated type are implemented - in a word, there is no control of the output voltage, of course this is quite bad, but it is not at all a necessary process if the amplifier is not sensitive to the supply voltage and is a cheap model. Converter transistors - they are the ones that fail most often. In cheap Chinese amplifiers, transistors are strangely marked, even if you cannot find similar transistors, you just need to know one thing - the keys can always be replaced with IRFZ40 / IRFZ44 / IRFZ46 / IRFZ48 or more powerful IRF3205, the choice of keys is actually quite large, I just listed the most available options. In general, N-channel high-power field-effect transistors are used exclusively in all inverters of automobile low-frequency transistors - up to the brutal IRF1404. Initially, we check the board by eye - sometimes visible defects can be observed (burned out resistor, broken tracks on the back of the board, etc.) Before replacing the transistors, you must first check the power fuse, the diode on the plus and minus buses (when the power is reversed, it also burns out), and only after you have made sure that everything is ok with these parts, we replace the keys. For a more professional repair, an oscilloscope is indispensable. Initially, you need to check the presence of rectangular pulses on the 9th and 10th output of the generator microcircuit, if any, then the microcircuit is working. Then we check for the presence of the same pulses after the driver - on the gates of the field switches. If there are no pulses, then most likely the problem is in the driver, if they are, then without hesitation we replace the field-effect transistors. It is extremely rare that there is a problem with the power amplifier, the converter burns out first, keeping the amplifiers. In the converter, other breakdowns are possible, although very rarely. There is a problem with the input and output capacitors or the diode rectifier, which rectifies the high frequency AC voltage from the transformer. A low frequency amplifier (ULF) is a device every music lover knows about its purpose. This component of the audio system improves the overall sound quality of the acoustics. But like any other electronic devices, AU can fail. For more information on how to repair amplifiers of car audio systems with your own hands, learn from this article. Before repairing, installing and adjusting the ULF in your car, you need to understand the breakdown. It is simply impossible to consider all the faults that can be encountered in practice, since there are a lot of them. The main task of repairing a device for sound amplification is considered to be the restoration of a broken component, the breakdown of which led to the inoperability of the entire board. In any electrical engineering, including amplifiers, there can be two types of faults: Automotive ULF microboard Repair of car amplifiers first of all starts with ULF diagnostics: Soldering iron on the amplifier chip Do-it-yourself car amplifier repair is carried out in accordance with what problem was identified during its operation: Now let's move on to the question - how to set up a car amplifier? There are several configuration options - for use with and without a sub. How to properly configure the ULF without a subwoofer - first you need to set the following parameters: After that, adjusting the settings of the audio system with an equalizer, the system is tuned to suit your preferences. The volume must be set to maximum and include some track. How to set up an amplifier in a car for use with a subwoofer is also not particularly difficult. For correct configuration, it is advisable to use the following parameters: It is very important to observe these parameters, since they determine the quality of the adjustment and, accordingly, the sound of the audio system. In general, the setup procedure is similar, using the level control to provide a more harmonious sound. The sensitivity of the rear and front speakers should be matched to each other. If you don’t understand anything about this, it’s better not to go there, because repairs will cost more after you burn or break it. Sorry, there are currently no polls available. In more detail, the recommendations and procedure for repairing the microcircuit are described in the video below (the author is the Soldering TV channel). UMZCH repair is almost the most frequent of the questions asked on amateur radio forums. And besides, it is one of the most difficult. Of course, there are “favorite” faults, but in principle, any of several tens, or even hundreds of components that make up the amplifier can fail. Moreover, there are a great many UMZCH schemes.
Of course, it is not possible to cover all the cases encountered in the repair practice, however, if you follow a certain algorithm, then in the overwhelming majority of cases it is possible to restore the device's operability in a completely acceptable time. This algorithm was developed by me from the experience of repairing about fifty different UMZCH, from the simplest, for a few watts or tens of watts, to concert "monsters" of 1 ... 2 kW per channel, most of which were sent for repairs without schematic diagrams. The main task of repairing any UMZCH is to localize the failed element, which entailed the inoperability of both the entire circuit and the failure of other stages. Since there are only 2 types of defects in electrical engineering: then the "super task" of the repair is to find the broken or broken element. And for this - to find the cascade where it is located. Further - "a matter of technology." As the doctors say: "The correct diagnosis is half of the treatment." The list of equipment and tools required (or at least highly desirable) during the repair: Consider this algorithm using the example of repairing a hypothetical transistor UMZCH with bipolar transistors in the output stages (Fig. 1), which is not too primitive, but also not very complicated. This scheme is the most common "classic of the genre". Functionally, it consists of the following blocks and nodes: We turn on the amplifier. The lamp should blink (while the filter capacitors are charging) and go out (a weak glow of the filament is allowed). This means that K.Z. on the primary winding of the network transformer there is no obvious short circuit. in its secondary windings. With a tester in the alternating voltage mode, we measure the voltage on the primary winding of the transformer and on the lamp. Their sum must be equal to the network. We measure the voltages on the secondary windings. They should be proportional to what is actually measured on the primary winding (relative to the nominal). You can turn off the lamp, put the fuse in place and turn on the amplifier directly to the network. We repeat the voltage check on the primary and secondary windings. The ratio (proportion) between them should be the same as when measured with a lamp. The lamp burns constantly at full incandescence, which means we have a short circuit. in the primary circuit: check the integrity of the insulation of the wires coming from the mains connector, power switch, fuse holder. We unsolder one of the reasons going to the primary winding of the transformer. The lamp went out - most likely the primary winding (or turn-to-turn circuit) is out of order. The lamp burns constantly in incomplete incandescence - most likely, a defect in the secondary windings or in the circuits connected to them. We unsolder one wire from the secondary windings to the rectifier (m). Do not confuse, Kulibin! So that later it would not be excruciatingly painful from improper soldering back (mark, for example, with pieces of adhesive masking tape). The lamp went out - it means that everything is in order with the transformer. It is lit - again we sigh heavily and either look for a replacement for it, or rewind. 6. It was determined that the transformer is in order, and the defect is in the rectifiers or filter capacitors. We call the diodes (it is advisable to unsolder under one wire going to their terminals, or to solder it out, if it is an integral bridge) with a tester in ohmmeter mode at the minimum limit. Digital testers often lie in this mode, so it is advisable to use a dial gauge. Personally, I have been using the “squeaker” dial tone for a long time (Fig. 2, 3). Diodes (bridge) are broken or broken - we change. Integers - we call the filter capacitors. Before measuring, they must be discharged (.) Through a 2-watt resistor with a resistance of about 100 ohms. Otherwise, you could burn the tester. If the capacitor is intact, when closed, the arrow first deviates to the maximum, and then rather slowly (as the capacitor is charged) "creeps" to the left. We change the connection of the probes. The arrow first goes off scale to the right (the charge from the previous measurement remains on the capacitor) and then again creeps to the left. If there is a capacitance meter and ESR meter, then it is highly desirable to use one.We replace broken or broken capacitors. The sound amplifier in the car is the main component for obtaining high-quality and clear reproduction of musical compositions. They are installed both separately from the car radio and inside it. Auto amplifiers, installed in a separate enclosure, have excellent power ratings and are capable of creating perfect sound. The main feature of this equipment is the power supply system, as well as operation in conditions of low humidity and significant vibration. Therefore, the repair of car sound amplifiers is a work to restore the performance of special electronic devices for highly specialized craftsmen. At the first even insignificant signs, it is recommended to immediately contact specialized workshops for the repair of this technique, because comfortable movement without a spacious and beautiful sound in the car is impossible. Among the first signs of amplifier failure are the following: Many modern audio signal power amplifiers for cars are equipped with several types of protections, therefore, when one of them is triggered, which means that the sound signal to the acoustics stops or the corresponding signal indication (if it exists, of course, exists on the device panel), you must immediately turn it off. them from food. This can be done in several ways: This procedure will allow you to continue driving without music, but with a working power supply generator-battery connection, before the failed car amplifier is sent for repair. Repair of car sound amplifiers depends directly on the type of this equipment and its class, and this applies to both troubleshooting, its elimination and, accordingly, the cost of such work. So, all car amplifiers are divided by the number of playback channels: Car audio amplifiers are also classified according to signal distortion and efficiency. There are four classes of amplifiers: The most common reasons that lead to malfunctions of audio amplifiers for cars are: In principle, high-quality and expensive car amplifiers most often serve their owner for a long time and do not require special maintenance or prevention, therefore, with proper installation and connection, they work without repair or damage. Recently, a friend asked to repair a car amplifier that had been lying in a repair shop for about a month, and as a result, the master asked for an exorbitant price of 2,500 rubles. Blaupunkt GTA-260 amplifier with a declared power of 400 watts. In fact, a good two-channel amplifier, though at the expense of power…. lies. A symptom of a malfunction is a short circuit between the positive and the power supply ground, the fuse is intact. After opening, the first thing I checked was the diode, it is natural to ring in both directions, but it is not yet necessary to solder it. In 90% of cases of such problems, the power N-channel field switches are to blame, which are in the input circuit and are designed to swing the power transformer, in this sample there were switches of the IXTP64N055T type, for 64 Amperes 55 Volts. And the problem turned out to be in them, both burned out. As a rule, in budget amplifiers of such a plan, where there is only one pair of keys in the inverter, I put the IRF3205, but only irfz44 was at hand, and I put them. Naturally, their maximum current is slightly less, but the difference in power will be imperceptible by ear, taking into account the fact that the amplifier worked with broadband acoustics, and not with a subwoofer. I did not even understand why the master asked for such an amount for repairs and was looking for a problem for about a month, a problem that can be identified without even opening the amplifier ... In general, this amplifier is built according to the standard topology - a push-pull inverter, based on the TL494 PWM controller, a node for high-speed discharge of the gate capacitance of field workers based on two low-power complementary pairs, field switches, a transformer, an output rectifier with a filtering unit and a power amplifier. There are two channels here, they work in class AB, the power, purely from practice, I will say that no more than 100-120 watts per channel. There is also a signal filtering unit for the operation of an amplifier with a subwoofer and pre-amplifiers, all this part is implemented on budget dual op-amps BA4558. Pleases the presence of a choke at the 12 Volt power input. The board for me is an "acetyl" bunch of jumpers, the components are crooked, if you are careful, you can see some "balls" of solder, I never liked blaupunkts. If anyone wants advice on choosing an auto amplifier, I advise you to look towards alpine, I have repaired and studied many amplifiers - only alpine can boast of real sound quality as well as the assembly and wiring of the board, and at the end, for comparison, my alpine mrv-f450 board. I understand that from a price point of view, it's like heaven and earth, but it's better to take a good one right away - I assure you that alpine has never been repaired, I don't remember what year without any complaints. Hmm ... about working in class AB, you went too far. Even your Alpine is not capable of holding 1 watt in class A.And the master spoke correctly, the brazen people went, they want to do everything for free! Sometimes, even from over 100r, a scandal is resisting! Today they brought such an interesting car amplifier for repair. According to the owner of the car, such an amplifier has been in the car since time immemorial. The amplifier is the most common - a four-channel transistor amplifier with a built-in voltage converter. Everything would seem to be fine, but here the emblem is LADA, was it really collected in Russia? Later, the documentation for the AL-100.4 was found on the Internet. Rated power, 4 Ohm 50 W x 4 Indeed, quite a powerful and good amplifier, judging by the board. A huge transformer immediately catches the eye - it is he who powers the entire installation - 4 amplifiers with a power of 100 watts each. Muscles are powerful field keys (they were exactly what burned out in this amplifier, but more on that next time). The power choke is wound on a ring from iron powder. Consists of 7 turns, wound immediately with 5 cores of 0.8mm wire. Powerful diode from power reversal. The generator is built on the traditional TL494 microcircuit with additional drivers to amplify the microcircuit signal. It is interesting that 2 drivers are used here (4 pairs of low-power transistors). Further, there are already powerful field switches of the 50N06 series. This is a fairly powerful series of field-effect transistors, there are 4 of them in the circuit, two transistors per arm. The power of the converter is more than 400 watts, this is by eye. The transformer itself is powerful enough, which has two secondary windings. The voltage is rectified using powerful (Schottky diodes (diode assemblies). Further smoothing capacitors of 2200 uF 35 Volts per arm. Each of the secondary windings feeds two amplifiers. In appearance, the AL-100.4 amplifier honestly gives its 4x100 watts, since both the power of the amplifiers and the voltage converter allow this. Next, we will consider the cause of the malfunction and repair of such an amplifier and a few more interesting facts. We continue the topic about the LADA AL 100.4 car amplifier. The converter with power amplifiers are mounted on one board. LPF summator and timbre block on a separate one. On the board we can see 4 completely identical power amplifiers. Each amplifier develops a maximum power of about 100 watts. The output stages are built on powerful bipolar transistors NPN-2SD718 (8A, 120V, 80W) and PNP-2SB688 (8A, 120V, 80W). This is a fairly well-known complementary pair that has found wide application in high-quality transistor amplifiers. Each of the amplifiers has one output stage and is powered by +/- 30 Volts bipolar voltage, so 100 watts for each amplifier is not a problem. The amplifiers can also be bridged, thus increasing the output power to 200 watts per channel. But in this case, the amplifier will operate in stereo. The reason for the malfunction of such an amplifier was in the voltage converter. In general, in almost all automobile amplifiers of increased power (with the use of PN) such a problem occurs. Of course, the amplifier is protected by a fuse, there are two of them, but the device protected by a fuse burns out first, having protected the fuse - this is not a philosophical expression, but the pure truth. According to the owner, the amplifier failed after he accidentally reversed the polarity of the power connection. Strange as it may seem, neither the fuse, nor the built-in protection, and even the protective diode from overplacing saved the amplifier. Power keys flew out at once, and there are as many as 4 of them in the circuit. Here are used quite powerful field drivers of the 50N06 series, in fact, they are almost complete analogues of the IRFZ44, so that you can replace it, but after checking the circuit in advance.It is quite simple to check the circuit for operability. You need to connect the power and check the generation of rectangular pulses at the 9th and 10th pin of the microcircuit. If there is generation, then you can safely replace them. In my case, IRFZ44 transistors were used. The amplifier is working as good as new! This completes the ULF repair. Keep in mind, before turning on any electronic device in the car (car radio or power amplifier), pay strict attention to the polarity of the connection, do not hope that the protections can be saved, practice shows that during real threats, none of them work , then you will have to pay a lot of money to repair expensive equipment. You are a condom. capacitor. and not a condenser. what a bitch do you say in a fagot? Excuse me, but you are the "condom", Sergei. On what basis are you insulting a person for such a trifle? If you do not like it, do not listen or watch this video. What is the problem? output transistors are ancient like mammoth shit. analogue of our KT819GM-KT818GM. Precisely noticed, only - KT825 - KT827 Well done. Try further and everything will work out for you. Put my thumbs up How to detach transistors from the case? they stuck to me. Is there any way to rip them off? Heat the case itself with a soldering iron. Transistor. Do not fry too much, or you will overheat. the transistors on the tip36c output stage burn out. burns out one. change it. the other is on, it plays quietly, you turn up the volume a little and burns out again. monoblock, transistors connected in parallel 4pcs tip36c and on the other side 4pcs tip35c. what is the problem ? one of the four tip36c burns constantly Dmitry Barsukov check the resistances, there are large transistors next to them. It shouldn't be so in principle Maybe it closes about the mass somewhere that's just the point, in all the videos that I found, they change one transistor or 2 and everything works. it also turned on for me, but when the sub is connected, one transistor burns out again. sub worker, checked with another usem. broke my whole head already Well, I changed one pair of transits and everything works great Amplifier copy Blaupunkt gta 470 Where is the final speaker test all channels? For your efforts like! Hey! Yes, I also had burned out transistors in 3 amplifiers being repaired (I have a video on the channel, if interested). Hi, for some reason I didn't even think to show it. In amplifiers, a transistor almost always burns out.
Video (click to play).
Views: 20 981
Category: Power amplifiers
Maximum power, 4 ohms 100 W x 4
Rated power in bridged connection, 4 Ohm 100 W x 2
Maximum power in bridged connection, 4 Ohm 200 W x 2
Recommended fuse rating 20 A x 2
Dimensions 290 x 57 x 243 mm
Signal to noise ratio> 80 dB
Vyebony is absolutely useless here. Learn to talk normally with people, without insults. Perhaps he will pull for constructive criticism. To whom it is convenient, he pronounces it. The main thing is that this moment does not change the essence of the video, not a drop. Just blowing a camel out of shit out of the blue, by God.
you change it, the VCL turns on, but it's worth connecting the sub and turning up the volume a little again, some one burns out. with another amplifier, the sub works fine
Video (click to play).
