Repair audio amplifier active column. Repair of automotive amplifiers Repair Car Amplifier do it yourself

Repair Amplifier Sound - As a rule, repair of the sound power amplifier, the master with extensive experience in the field of radio electronics begins with a visual inspection of the instrument's printed circuit boards in order to identify burnt or darkened electronic components. In the order of the outflow, the item is best minted, so-there is first need to reveal a not working cascade , and then identify the component caused the cause of the inoperability of the amplifier. The value of the test follows from the output stage, during the inspection, without applying the measuring instruments of the type of multimeter, but simply when the power supply is turned on and the input signal is turned on, you need to touch the dry finger to the powerful terminal cascade transistors or The same output chip and determine the temperature of the part of the part.

If the output transistors are generally cold, then this suggests that there is no passing current in the chain, which should warm these components in the usual standard mode, or vice versa, if the part of the breakdown is so impossible to hold the finger on it, then this is also a consequence of a malfunction. "The method is also checked by a voltage stabilizer, in particular, the electrolytic capacitors of a large capacity, if they are heated or there are traces of height and bloating, they need to be changed, in general, this applies to all electrolytes installed in the scheme. Also with visual inspection in order to detect poor contact to printed circuit board, you need carelessly with a screwdriver to catch up with a fee, disappearing contact will be revealed to outsiders sounds And a crash in the speakers.

Next, you need to check the multimeter of the variable and constant voltage of transistors and the chip. After finding a faulty item is very important to determine because of which this item could fail to eliminate such a phenomenon. After you have done actions, you can proceed to replace the component on exactly such a thing. Detail or its analogue. The defects in the power supply should be carried out from inspection of the network wire and checking the fuses if everything is fine and the network voltage is present on the primary winding of the transformer, and there is no on the output secondary winding, it is possible in the transformer on the primary winding. A fuse, which caused the absence of voltage in the secondary chain, and if there is no installed fuse, it means there is a break in the primary winding, in this case the trance will have to rewind or search for suitable and output voltages.

Another cause of the inoperability of the amplifier can be an ordinary short circuit of the output circuit on the housing or to a general wire. In the amplifiers built on chips as the output stage of amplification, then when the chip is faulty, it simply changes to another obviously good, and if you can not find a suitable optional parameters You can instead of the burnt to put an ordinary low-frequency amplifier type TDA, which does not require strapping with additional elements, so the replacement of any faulty power amplifier on the TDA series chip will not be difficult.

According to the owner of the car, such an amplifier stood in the car from time immemorial. The most common amplifier is a four-channel transistor amplifier with a built-in voltage converter. Everything would seem normal, but then the emblem is Lada, did you really collect in Russia?

Later on the Internet there was a documentation on Al-100.4.

Rated power, 4 ohm 50 W x 4
Maximum power, 4 ohm 100 W x 4
Rated power in the bridge inclusion, 4 Ohm 100 W x 2
Maximum power in the bridge inclusion, 4 Ohm 200 W x 2
Recommended Nominal Fuse 20 A x 2
Dimensions 290 x 57 x 243 mm
Signal / noise ratio\u003e 80 dB

Indeed, a fairly powerful and good amplifier, judging by the board. Immediately striking a huge transformer - it is that it feeds the entire installation - 4 amplifier with a power of 100 watts each. Muscles are powerful field keys (they are burned in this amplifier, but about it next time).

Power throttle is wound on the ring from powder iron. It consists of 7-and-turn, wounds at once with 5-residents of the wires of 0.8mm. Powerful diode from food surplus.

The generator is built on the traditional TL494 chip with additional drivers to enhance the microcircuit signal, it is interesting that 2 drivers are used here (4 pairs of low-power transistors). Next, the powerful field keys series 50N06. This is a fairly powerful series of field transistors, in the scheme of them 4, two transistors on the shoulder.

The power of the converter is more than 400 watts, it's on the eye. The transformer itself is quite powerful, which has two secondary windings. The voltage is straightened with the help of powerful (Schottky diodes (diode assemblies). On the smoothing capacitors of 2,200 μF 35 volts on the shoulder. Each of the secondary windings has two amplifiers.

In appearance, the amplifier Al-100.4 honestly gives its 4x100 watts, since the power of amplifiers and the voltage converter fully allow this. Next, we consider the reason for the malfunction and repair of such an amplifier and some more interesting facts.

We continue the topic about the car Lada al 100.4. The power amplifier converter is mounted on the same board. FNH Summator and temboards on a separate. On the board we can see 4 fully identical power amplifiers. Each amplifier develops the maximum power of about 100 watts.

The output cascades are built on powerful bipolar transistors NPN-2SD718 (8A, 120V, 80W) and PNP- 2SB688 (8A, 120V, 80W). This is a fairly well-known complimentary couple, which has been widely used in high-quality transistor amplifiers. Each of the amplifiers has one output stage and feeds from two-polar stress +/- 30 volts, so that 100 watts are not a problem for each amplifier.

Also, the amplifiers can be included on the pavement scheme, thus increasing the output power up to 200 watts per channel. But in this case, the amplifier will work in stereo mode. The cause of such an amplifier was in the voltage converter.

In general, in almost all automotive enhancers of high power (with the use of PN) there is such a problem. Of course, the amplifier is protected by the fuse, their as many as two, but the device protected by the fuse burns first, defending the fuse is not a philosophical expression, but pure truth. According to the owner, the amplifier failed after he accidentally confused the polarity of power connection. As not strange, neither the fuse nor the built-in defense and even the protective diode from the surveillance did not save the amplifier ...

Immediately flew by power keys, and they are in the scheme for as many as 4 pieces. It uses fairly powerful stools of the 50N06 series, in fact, they are almost complete IRFZ44 analogs, so that you can replace, but checking the scheme in advance. Check the scheme for performance is quite simple. You need to connect the power and check the generation of rectangular pulses on 9 and 10 the output of the microcircuit. If generation is there, then you can safely replace them. In my case, IRFZ44 transistors were used. The amplifier earned as new!

This repair UHC is completed. Keep in mind before turning on some kind of electronic device in the machine (car radio or power amplifier) \u200b\u200bpay stirrely on the polarity of the connection, do not hope that protection can save, practice shows that during real threats, none of them works , then you will have to pay considerable money for the repair of expensive equipment.

Repair of amplifiers

Troubleshooting usually leads in the following sequence:Determination of a faulty cascade in the device. Cascade Fault Looking. Analysis of the causes of the failure of the part. Selection and replacement details. Postgraing check and adjust the cascades in the device.

With a non-working sound frequency amplifier, you can touch your finger to the output chips or transistors. If they are cold with normal supply voltage and input signal, it does not undergo current, which in normal mode should warm them. If transistors are very hot, this also speaks of a malfunction. The stabilizer is also checked. Warm electrolytic capacitors of the high capacity of filters or with signs of breakdown are also subject to replacement.
With an external inspection, you can slightly tap the screwdriver handle. If contact disappears, cracks and root will appear when touched to the machine. To find a malfunction, make measurement of transistor modes or microcircuits on constant and variable current.

The disfect of a network power supply is determined from checking the healthcur and fuses. If the fuses are intact and network voltage comes to the primary winding of the transformer, but there is no voltage at the output, the fuse is integrated into the transformer. This fuse is present in most transformers and is fixed over the primary winding. If this fuse is not, and the break in the primary winding, the transformer will have to be changed. It should be found out what should be secondary voltages and choose the finished transformer or even put two if the transformer has failed to find with all the necessary voltages. To find out the value of voltages in the secondary winding circuits, if you determine the passport supply voltage by one of the output chip. The lattaval inscriptions on the power filter capacitors will also help. As a rule, they are put with a 30% margin.

The failure of the sound power amplifier often occurs due to the closure of the output of the amplifier to the overall wire or body. In most instruments, power amplifiers are made on chips, and repairs consist in a simple replacement of the microcircuit. But there are cases when finding a similar chip is difficult, and it is impossible to choose an analogue. If the Uncle scheme could not be found, it is possible to repair the device using instead of the burned chip, standard UNUC on TDA 1552 - TDA 1558. These chips do not require almost no attachments and replacing any integrated power amplifier to one of these chips will be very simple.

Low frequency amplifier (UNG) is a device, which is about the purpose of which each Meloman knows. This component of the audio system allows you to improve the quality of the sound of acoustics as a whole. But like any other electronic devices, AU may fail. More information about how to repair with your own car audio amplifiers, find out from this article.

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Typical malfunctions

Before repairing, installing and configuring UMH into your car, you need to figure out the breakdown. Consider all the faults that can be found in practice is simply impossible because there are a lot of them. The main task of repairing the device to enhance the sound is considered to be the restoration of the broken component, the breakage of which led to the inoperability of the entire board.

In any electrical engineering, including amplifiers, there may be two types of faults:

contact is present where it should not be;
in the place where contact should be, it is missing.

Check for performance

Repair of automotive amplifiers primarily begins with Diagnostics UCH:

First, you need to open the case and carefully examine the scheme, if necessary, use a magnifying glass. During the diagnostics, you can notice the destroyed components of the scheme: resistors, capacitors, torn conductor or burned road tracks. But if you found the burnt component, it is necessary to consider that its failure may be the result of the brave of another element, which can seem to be intended.
Next, make the diagnostics of the power supply, in particular, check the output voltage. When identifying burnt resistors, these elements will need to be changed.
Serve power to UNUC and Remout output, then you need to close the system on the plus and look at the Protection diode indicator. If the light bulb caught fire, it suggests that the device went into defense. The reason may be in poor nutrition or its absence on the board, breaking the transistor or problems in the operation of the voltage converter. In some cases, the cause lies in the transistor power supply breakage for one of several channels.
If after power is supplied, the safety element has not burned, you need to check the voltage level at the output. It should be approximately 2x20 V and more.
Carefully inspect the voltage transformer transformer, perhaps there are burnt turns or chain breaks. Smoke this element, maybe it smells burnt. In some unch models between the PN and the amplitude, a diode assembly is installed - if it fails, the node may also include protection.

Elimination of breakdowns

Repair of the automotive amplifier with their own hands is carried out in accordance with what problem was identified during its work:

If a transistor broke into the autocessor, then before it is directly replaced, it is recommended to distribute the safety element for nutrition. Also you need to make sure the performance of diodes on tires. If everything is in order with these parts, the installed transistors must be changed.
To carry out more specialized repair, you will need an oscilloscope. By installing the device's probe on the outputs 9 and 10 of the generator cards, you need to make sure that the signals are available. If there are no signals, the driver changes if they are, then the field transistor elements are replaced.
Capacitors change significantly less often in the repair process - as practice shows, it happens infrequently (the author of the video is the Hamradio Tag channel).

Main aspects of the amplifier setting

Now let's go to the question - how to set up a car amplifier? There are several settings options - for use with sabo and without it.

How to configure UCH without a subwoofer - you must first set these parameters:

bass Boost - 0 Decibel;
level - 0 (8V);
the crossover must be installed in the Flat position.

After that, adjusting the settings of the audio system by the equalizer, the system is set up under its preferences. Volume must be put up to the maximum and include some track. How to configure for use with a subwoofer - the procedure is also not particularly complex.

To properly configure, it is advisable to use the following parameters:

Bass Boost should also be set on the level of 0 Decibel;
the level is set to 0;
the front crossover is installed in the position of HP, and the FI PASS regulator must be set in range from 50 to 80 hertz;
as for the rear crossover, it is installed in the LP position, and the LOW regulator must be set in the range from 60 to 100 hertz.

These parameters are very important, since they determine the quality of the adjustment and, accordingly, the sound of the audio system. In general, the setup procedure is made similarly to this, the level controller is used to provide more harmonious sound. The sensitivity of the rear and front speakers should be adjusted to each other.

If you do not understand anything, it's better not to climb there, because the repair will cost more after that you still burn or break.

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Master's answer:

Experienced in the repair of radio electronics wizard. Checking devices, in particular, sound amplifiers are performed in a specific sequence. How to do and you. So first you need to identify non-working cascade in the device and find faulty items in the cascade. After that, analyze the cause of the damage to the element, and then select and replace the element. Repair Completely check and adjust the cascades in the device.

So, if your sound frequency amplifier refuses to work, then you need to start to determine by touched the fingertip to the output transistors or chips them. Cold elements with normal supply voltage and input signal indicate the absence of current, which must heat them under normal conditions. Overly hot radio components, too, cause malfunction. The stabilizer is also checked with touch. The replacement is the heating capacitors-electrolytes with a significant container of filters or with visible samples of breakdown.

During the visual inspection of the amplifier, they will slightly knock on the board with a screwdriver. Dissaging contact will be determined by crackling and rustles in the sound of music. To identify a malfunction, measure the operation of the microcircuits and transistors over the variable and direct current.

Before looking for a defect in the power source, you need to inspect and check the power cable and fuses. In the case of the complete integrity of the fuses and the presence of a voltage of the network submitted to the primary winding of the built-in transformer, there is no voltage at its output, then the fuse is most likely built in the transformer, which is attached from above the primary winding. The transformer is certainly subject to replacement if there is no fuse, and the break is in the primary winding.

According to the secondary voltage parameters installed by the manufacturer, select and install the transformer. In the absence of it, you can put 2 transformers. The voltage that is fed to the secondary winding circuit can be found on the passport data of the output microcircuit. No less useful for you will be to indicate a voltage on the power filter condenser: the voltage is indicated with a 30 percent reserve.

A frequent cause of the breakdown of the audio amplifier is a banal closure of the device output to the body or shared wire. The latest modifications of sound amplifiers operate on chips, and therefore the repairs consist in the usual replacement of a faulty chip. But if such a chip could not be found for some reason, it is possible to produce UH repair, if instead of a damaged chip, establish the usual UNG TDA 1552 - TDA 1558. These chips do not require attachments, and therefore replacing any of the faulty power amplifiers on the microcircuit will be quite simple.