DIY amplifier repair Vega 10u 120s

In detail: do-it-yourself repair of the Vega 10u 120s amplifier from a real master for the site my.housecope.com.

They brought it to the repair quite often with basically the same malfunctions, due to the fact that they tried to "squeeze" everything out of it,

what is possible and even more. I will describe the breakdowns that I had to do most often.

Image - DIY amplifier repair vega 10u 120s

Due to overloads, microcircuits DD1, DA2, DA3, DA2.1, DA2,2 failed most often (k157ud2 - a large signal was applied to the input). To speed up the repair, panels were soldered under them. Instead of transistor assemblies, I selected with the same gain and soldered KT3102 transistors.
Output transistors VT 28-VT30 check for insulation from the radiator.
Check resistors R77-R80 together with output transistors.

Sergey Talmenka

    unfortunately there is nothing in my pocket, as always. but I want to do it.

Phlanger

    then we take the sovetskiy pointer avometer, take Borisov's book, cut the fuck out of your internet. True, it will take five years and only horns and legs are guaranteed to remain from the subject Vega along the way, but a solid profit is not excluded at the exit

K. Gereev

    so it is necessary to study, but then I just asked and everything sings

Bormann

    Sergey Talmenka
    Do you generally receive sound after the switch to the amplifier? somewhere there was a pair of dry 10 microfarads and the sound does not pass. Did the conders change the polarity? can you solder? Sukhpayev not done? did not close the paths?

    I have a normal soldering iron and learned how to solder from childhood, but it was the electrolytes that I changed all of them there.

    It’s not too early to study, and when it’s not too late, but I asked about it and kept singing, I don’t count on it, I know that it won’t sing itself,
    Of course, I'm not a specialist, but we don't have them in the village, so I'm trying to do what I can myself (thank God the Internet helps),
    So I ask all the proffies where to look after the conductors and transistors, because I checked them all too.

Video (click to play).

mart

    The circuit is in front of your eyes, the sovetsky analogue avometer, as Dmitry advises, should be placed next to the amplifier, the “TON” capsule with a 0.1 microfarad capacitor. For fun, measure the voltage. If it does not work, then simply determine with an earpiece where the signal disappeared in the circuit. And there is a matter of technology.

    unfortunately there is only a digital multimeter, and today I will look for a signal with an earphone.

Jupiter5700

    If all the electrolytes are changed to new ones, but there is still no sound, then, firstly, there is a possibility that the preamplifier has flown out. Give a signal bypassing and check if there will be a sound. Second, check the output transistors. If there is no oscilloscope, then you can drive the entire signal path through the headphones by connecting 0.1MKf capacitors in series to their input.

Andreys

    Explained 100,500 times.
    -We download the scheme. We print. In 3 copies. We take colored pencils and on one we draw how the food goes, with all its pros and cons, and on the second - how the sound goes.
    -we take a tester in our teeth and measure the food. Right on the same diagram, we write what is wrong.
    - we take high-impedance ears and look at the passage of sound. Directly on the diagram we draw where it is and where it is not.
    - we look at the diagram and think a lot.

Andrey N.

    maybe I'll ask nonsense, the plug is wired correctly.
    before there was one plug at work, and at home it was with a different wiring, maybe the wiring where it fell off in the plug, otherwise somehow I did not see about it so that the author wrote

Sergey Talmenka

    Jupiter5700

    output transistors checked-working.

    Thanks for the advice, by the way, at the expense of a lot, we think this is generally correct.

    I checked the cord that I connect from Olympus (they are all standard wiring, it seems like) just in case - everything is in order, on the weekend I will follow the scheme as explained to look and search.

Electron

    How many domains about this vega have been remagnetized, but still new topics.

    Do you think I have not watched them? Everyone has a different problem. but soon we will write legends about Vega.

Phlanger

    No no no. First, we require a nanny to bring in the dedomorosa, so that he gets it out of the shy rods, or where he hides for himself - old man
    so that he whispered over these Voices “daragayaridaktsya. "
    and will immediately become shyayte. Well, how is it - a duck in a hare, a grandfather for a turnip. remember?
    And if there are no books, no voltmeter, no desire to even understand what it is, one oh! Fagot with these your enturnetame. well, we'll jerk off oh! paminaitminipampeers. "
    over 9000 cases
    And here is Chyudatvorny Knopaseka “call of the nanny”. I don’t remember who didn’t believe me.
    https://my.housecope.com/wp-content/uploads/ext/580/uploads/20160506/1. 892355.gif
    Is it from her that the legs of this dementia grow?

    Do you think I have not watched them? Everyone has a different problem. but soon we will write legends about Vega.

    It was necessary not to look, but to read.
    And the problem for everyone who is trying to fix a primitive amplifier by reading forums is the same.
    And it will be repeated for YEARS.

    Think for yourself, there are two channels. They do not break at once, which means that something in common has broken.
    For example - wrong cable or volume control.

Anton Temnikov

    The case is very difficult. Do you think someone would like to sit with a diagram and treat from a photograph?
    Here is the answer to all your questions:
Video (click to play).

Sergey Talmenka

    I study, read, try, search - on the weekend I will continue, I downloaded the scheme in a large size, glued it together, then there’s no time, the vegetable garden is waiting, I’ll rake it up for a couple of days and continue again.
    I will write about the results.

    • Image - DIY amplifier repair vega 10u 120s

    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 (hair dryer, SMD-hot tweezers, etc.), a schematic diagram, not to mention the necessary knowledge and repair experience.

    Let's consider a situation if you are a beginner / advanced radio amateur soldering all sorts of electronic gizmos and having 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 are replacing this radio element with the same one - it is not yet 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 radioelements are almost everywhere used;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 repair the radio equipment on your own, 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 you post about the breakdown, the more chances you will get a competent answer. Understand that the forum is a system of gratuitous mutual assistance for 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 keep in mind that no one should answer instantly or during, say, a day, 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 stumped and decide to go to the forum. If you outline the entire 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.

    Due to the burnt out FU and R97, you have such a voltage imbalance.

    Is the R64 really singed? There is nothing to even “warm up” 330kOhm in this amplifier, let alone burn it.

    Not R64 but R78. There, on the board, they stand side by side, and the R64 marking is next to 78.

    Not R64 but R78. There, on the board, they stand side by side, and the R64 marking is next to 78.

    Due to the burnt out FU and R97, you have such a voltage imbalance.

    Is the R64 really singed? There is nothing to even “warm up” 330kOhm in this amplifier, let alone burn it.

    It's not scary 40 degrees (in fact, 65. 70 is acceptable) - it's scary that in 30 seconds.
    I once had - they replaced a burnt weekend, they began to get very hot and soon died again.
    It turned out that the bias chain was in the OPEN. Check it out more closely. In your scheme, these are T15 and T16, as I understand from the fragment posted here.

    In general, I often practice such a barbaric method - I solder the weekend, connect the speaker with a higher impedance (preferably 4A32) and listen to how the preout works.
    If it plays at a low volume without clearly audible distortions, I already carry out a full-fledged launch.
    So it turns out to fix it with a little blood, do not burn the transistors in packs.

    This should have been done not tomorrow, but yesterday when trying to turn it on after the "repair": because without controlling it when turning it on, you can burn again.
    You are inattentive, or you do not read the links given to you - five days ago already. My first, point 9, is about the quiescent current.

    “In general, I often practice such a barbaric method - I solder my weekends, connect a speaker with a higher impedance (preferably 4A32) and listen to how the preout works.” - IMHO it's not barbaric, it's quite normal. For the weekend burns first.

    Such gaskets are sold in different parts of rubles for three different ones. It's usually easier to buy. Seemingly the price tag is called either “thermal pad” or “insulating thermal pad”. The essence reflects not quite correctly, but the people are not confused.

    The thing is really comfortable. Especially in terms of the fact that, unlike mica, it is very difficult to move it. Recently I changed my weekends in K212, I didn't even bother with mica.

    Does the adjustment affect the temperature? Is the power imbalance corrected? How does the voltage drop change across R77, R78, R80?
    Maybe the preamplifier is dead (K57UD2)?
    Are the speakers not killed by the constant at the output when the faulty one is turned on?

    I apologize for the question in someone else's topic. I also decided to restore the Vega 10U-120S amplifier. The problem is this, plugging into the network, in the left channel the background to the speaker, the right channel is playing normally. At the output of the left channel, there is a constant of 23 V. As I understand it, almost all the transistors have died? Power supply after diode bridge + 26.2 V and - 24.3 V. There are no obvious burnt-out parts, a burnt-out resistor R97 (it gets very hot within 30 seconds). The amplifier was under a seal, no interference was visible. I replaced the electrolytes on the board, before the electrolytes were replaced, the left channel was also phoning. If, without cursing, I ask for specific tips where to start the check, if not hard, tell me which elements to watch?

    In my practice, it was such that the K561LA7 protection microcircuit was stupid, after its replacement the amplifier started working. And in general, the protection in the amplifier is configured to operate from a short circuit at the output of the UM. Feel the terminal transistors, they do not heat up.

    Added after 2 minutes
    Check the power supply on the 561 microcircuit on the 14th leg should be +12 volts.

    Added after 14 minutes
    There is also a cunning thermistor attached to the radiator, it also needs to be checked.Immediately replace the C43 electrolyte in the circuit of the D.D1 microcircuit.

    Added after 14 hours 48 minutes
    If you ask questions, try not to disappear for a long time!

    I have the same problem with 5-10 mins shutdown and hang up. It works on overheating similarly (the hand does not tolerate the heating of the radiators).
    Before that, he was generally half-alive, one channel worked in a booming middle, the second barely sang inaudibly, replaced all (except 43) electrolytes, 2 channels started working, but began to cut down. The tip shows that someone has already re-soldered it.
    Where to dig?
    Thanks in advance.

    PS I will not be lost, I have been reading the forum for a long time, I did not write simply.

    What is it like? Either whole or not. In this amp, everything is extremely simple. You turn it on without weekends, check the zero at the output, the power supply is normal or not, you start up the sinusoid - you look at the oscilloscope, whether the limitation starts evenly when the level increases. Thus, you evaluate the performance of the circuit indirectly, then you seal the ends, carefully check everything. And you check the quiescent current, perhaps you have it twisted to the maximum.

    zs This method will not work with Vega 122.

    Can you solder by heating a gas soldering iron? if there is no soldering iron. Image - DIY amplifier repair vega 10u 120s

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