The electronic control board of any type of stabilizer contains many components, including microcircuits, which cannot be tested without special equipment. But it's worth it carefully inspect the board itself and check the components on it for traces of high temperature.
Overheated resistors are the first to "catch the eye" and sometimes carbonize to such a state that it is impossible to recognize their markings - you will have to study the stabilizer circuit. Overheating of the resistors indicates a breakdown in other elements of the circuit - most often in power transistor switches. A close examination of the transistors can reveal blackening from overheating, and even mechanical cracks.
The cause of a malfunction of any circuit can be a breakdown in the capacitor. Very often electrolytic capacitors swell, which is why they differ significantly in shape from other capacitors. But the breakdown of a capacitor can not always be determined by its swelling - the electrolyte inside can dry out, from which it will lose its electrical conductivity.
On the board itself, traces of the impact of freelance overcurrents can also be seen - some tracks may burn, and the contacts may be soldered off, or close together due to the spreading molten solder heated by large currents. In addition, traces of strong heating of parts may remain on the board - from a change in shade to charring of the PCB.
Visual inspection of the defective module can tell the technician in which direction to diagnose. But, as a rule, the repair of electronic boards of stabilizers is not limited to replacing clearly damaged parts and requires additional checking of various components using special equipment. Therefore, if the continuity of the power transistors and other elements did not reveal the cause of the breakdown, it is better to take the electronic board to the workshop.
VIDEO
Today we will consider a list of basic malfunctions of voltage stabilizers of various types with a description of the causes of occurrence and methods of their repair.
Today we will consider a list of basic malfunctions of voltage stabilizers of various types with a description of the causes of occurrence and methods of their repair.After all, not every breakdown of a voltage stabilizer requires service repair, especially after the expiration of the warranty period.
About the internal structure and types of stabilizers
Of all the varieties of voltage stabilizers, three most common topologies can be distinguished with rather specific conversion principles. Among them, it is impossible to single out the most reliable one, too much depends on the nature of the power supply and the type of load, as well as on the quality factor of the device. In our review, we will consider servo, relay and semiconductor converters, features of their operation and typical malfunctions.
In a servo-driven stabilizer, the main functional element is a linear transformer with a multitude of mid-point leads of the secondary, and sometimes the primary winding - from 10 to 40, depending on the accuracy class. The ends of the leads are assembled into a collector comb, along which the collector carriage moves. Depending on the effective voltage on the power line, the stabilizer corrects the position of the carriage, thereby adjusting the number of involved turns and, accordingly, the transformation ratio. At the output of the circuit, a more fine adjustment of the voltage can be carried out, for example, using integrated semiconductor stabilizers.
Relay transformers are designed in a similar way. The number of transformer terminals is smaller; instead of smooth regulation, the fine tuning is achieved by recombination of the windings included in the operation. Power relays with a complex configuration of a relay group are responsible for operational switching. As in the previous case, there may be additional filters, stabilizers and protection devices at the output, however, the main work is performed by a transformer and relay assembly under analog control.
Electronic voltage stabilizers can be based on two conversion principles. The first is switching the transformer windings, but with the help of symmetrical thyristors, and not relays. The second principle is the conversion of current into direct current, its accumulation in buffer capacitors (capacitors), and then the reverse conversion into a “change” with a pure sine wave by means of a built-in generator. At first glance, the circuit seems to be quite complicated, but it provides an unprecedented high stabilization accuracy and high-quality line protection.
Of course, there are other stabilizer schemes, including hybrid ones, but due to their highly specialized use or archaic nature, we will not consider them. Each of the three most common families has so-called childhood illnesses or congenital deficiencies in technology. And therefore, the most important task before sending the device to the service center is to establish whether the breakdown is the cause of non-compliance with the maintenance standards or an ordinary malfunction for this type of stabilizer.
Typical faults of relay devices
Relay stabilizers are characterized by an optimal ratio of cost and reliability. The relay group is exposed to the main wear, and with frequent or constant operation in the mode of increased load, also the dielectric insulation of the transformer windings.
It is quite easy to diagnose a relay as the cause of a malfunction. The first step is to dismantle the components from the printed circuit board; they can be distinguished by a compact rectangular case, sometimes made of transparent plastic, with at least six pins. To determine the purpose of the terminals and the switching scheme, you can refer to the circuit diagram or technical specification for a specific type of relay according to the marking on the case.
You can make a test switching on of the relay, for which the operating voltage is applied to the contacts of the coil, as a rule, it is indicated on the case of the product. The absence of a click when connecting is a clear sign of a burnt coil or stuck contacts.If a click is heard, but when the group of the main contacts is ringing, the circuit of their switching is not observed, the problem is most likely in the mechanism of rejection and pressing, or in charred contact pads.
A significant part of electronic relays has a collapsible housing and can be serviced: restoration of the mechanism, cleaning the contact pads from carbon deposits with an eraser, sometimes even replacing a faulty coil. However, the best solution would still be to purchase new relays to replace the failed ones according to the article number or the location of the terminals.
The loss of dielectric strength of the transformer due to overheating is accompanied by interturn short circuits and is externally observed as darkening or destruction of the winding insulation. The main feature is a significant decrease in resistance below the passport standards.
Since most budget stabilizers have one solid primary winding and a multi-pin secondary, rewinding is not particularly difficult. In each link, the number of turns is small, they can be neatly laid even without a spindle or other winding devices. The most important thing is to accurately observe the number of turns and the direction of laying, as well as to correctly determine the initial resistivity of the conductors, and not just purchase a winding wire by diameter.
Another type of transformer malfunction is the operation of a semiconductor thermal fuse, which is usually included in the rupture of one of the windings. To replace a semiconductor element, it is enough to clarify its series or basic parameters in order to select an analogue. Usually, the thermal fuse is connected in series with the first link of the secondary winding, so all outer turns will have to be removed to access it. The problem is diagnosed simply: between the beginning of the winding and the first tap, the circuit does not ring, but all the other turns are in perfect order.
Broken servo stabilizers
The main reason for failure of servo drives is obvious: wear of the collector assembly. It is this shortcoming that is included in the category of childhood diseases that cannot be eliminated in most models of budget technology.
There are two types of slip mechanisms. At low loads, conventional spring-loaded brushes do an excellent job of switching the windings. The device completely repeats the principle of operation of the collector motors of the power tool, except that the collector itself is deployed from a cylindrical position to a plane. The second type of current collectors has a brush assembly in the form of a roller, due to which friction during movement is reduced, which means that there is no intensive wear of the lamellas. At the same time, the wear rate of tile and roller brushes is approximately comparable.
The disadvantage of a slip ring stems from its geometry. The contact spot is very small - only the line of contact of the cylindrical roller to the plane. True, in the most technically advanced models, the lamellae have radius grooves, although this solution is not entirely justified: as the graphite roller wears out, the contact area inevitably decreases. Depending on the intensity of use, replacement of brushes is required at intervals of 3 to 7 years. The situation can be aggravated in the presence of a large amount of dust and carbon deposits - up to the short circuit of several windings or a complete loss of contact.
Although servo regulators are also susceptible to overload operation, their transformer will wear less. Unlike relay devices, in which voltage and current surges occur regularly during switching, the collector unit adjusts more smoothly, due to which the mechanical effect of the current is minimal. The varnish insulation of the windings still dries up and becomes brittle, but it does not crumble.
Basically, the principle of operation of the servo stabilizer is extremely transparent.If, when turned on, there is an indication of the input voltage, but the device does not respond, the fault lies either in the drive itself or in the control and measuring circuit. In the latter case, a faulty circuit element can be easily detected purely visually or by dialing. If there is no voltage at the output, the transformer is faulty, but if the proper stabilization accuracy is not ensured, the presence of an interturn short circuit in the secondary winding, collector contamination, wear of the current collector brushes or the lamellas themselves are evident.
Common problems of electronic devices
Inverter stabilizers are considered the least maintainable at home. There are several reasons for this, but the primary one is the need for special knowledge in circuitry and, in particular, the principles of operation of switching power supplies. It will not be possible to do without an appropriate material base: soldering equipment with temperature control, as well as measuring instruments. The set of diagnostic tools goes far beyond the limits of a conventional multimeter, you will need a device with an extended set of functions for measuring capacitance, frequency and inductance, and it is also desirable to have a simple oscilloscope at your disposal.
The most common cause of malfunctions in inverter stabilizers is a malfunction of the clock generator. It is necessary, based on the rated power of the device and the parameters of the transformer, to determine the optimal operating frequency of the pulse converter, and then compare it with the real parameters. Frequency failure is usually caused by a malfunction in the reference oscillating circuit connected to the corresponding pins of the clock IC.
A complete failure of the device is possible for a number of reasons. If there is no built-in diagnostic system, or it is impossible to determine the breakdown by its indications, most likely the cause of the malfunction was the failure of the field or IGBT keys, which is quite simple to determine by the appearance of the case. Another typical cause of malfunctions is a breakdown of the built-in power supply of the control circuits; this part of the circuit is most vulnerable to voltage fluctuations, especially impulse ones.
It will not be superfluous to make a continuity of all circuits, their conductivity must correspond to the circuit and electrical diagrams of the device. The most vulnerable elements include input and output rectifiers, transformer snubber circuits (for suppressing surges), as well as a power factor corrector, if any.
General recommendations
Electronic components are found not only in inverter stabilizers, they can be used in control and measuring circuits or indication and self-diagnosis devices. This mainly concerns passive elements and microcircuits with a low degree of integration: operational amplifiers, logic elements, combined transistors, current and voltage stabilizers.
Failure of these elements can most often be determined purely by external signs: burnt out transistors and diodes have a cracked case, resistors - traces of burned varnish, capacitors simply inflate. Therefore, a close external examination of the printed circuit board is the first step in determining the malfunction.
If it is not possible to visually determine the cause of the breakdown, a sequence of control measurements should be made. First, the conductivity and quality of the dielectric insulation of the circuit is checked in the off state. After that, when power is applied, voltages are measured at key points: at the connection terminals, after the fuse, on filters and stabilizers, transformer windings, and the main nodes of the control circuit.
If the described diagnostic methods do not give a result, it is better to contact a service center, because even a simple breakdown can be very specific, despite the fact that amateur knowledge in electrical engineering and home conditions is not enough to eliminate it.published by my.housecope.com/wp-content/uploads/ext/941
If you have any questions on this topic, ask the specialists and readers of our project here.
It gets very hot, 245 volts at the output, it all starts with an inoperative power button. I have two such miracles hanging.
1. What is the load of each.
After answering these questions, we will continue.
250
300 V
60 Hz
Write down the status of the indicators.
Can you get a current clamp for a while?
Sincerely, ALEX.
Tomorrow morning I'll go for a tester 😈 I'll measure the voltage on the transformer, if I'm lucky, I'll scan the printed circuit board. I will throw the photos on my gigaportal on the People, I will insert the links into the message.
Added after 17 hours 17 minutes 8 seconds:
The third miracle has arrived.
Trance Findings: 0,12,180,210,240
PCB marking:
On the board, a 14-legged mikruha in a classic case (like K561LA7, for example):
Device Behavior - Four Options
25-50 Hz
In.
I will describe on yarn on trance and mikruh later 😳
Especially dangerous, armed with a hammer and a screwdriver.
It's a pity there is no such device at hand - I would disassemble and see what's what.
But I think it's not that difficult. We have an autotransformer with taps for a different input voltage range - 3 taps, a tap / winding for the electronics power supply (if the tap is bad, we have a galvanic connection with the network - we need to work carefully.) The electronics board must have a reference voltage source, comparators and keys with relays ... (correct if where you made a mistake.) The relays, depending on the magnitude of the input voltage, switch the taps of the autotransformer to keep the output voltage in the “operating window”.
LM324N - four opamp in one package - is convenient to use as voltage comparators to compare the input voltage with the reference voltage.
If the relays "hum" - check / replace the bridge and electrolyte in the power supply circuit of the electronics board. Is there a 3-pin xxx78xxx voltage regulator of the transistor type? if so, check / replace the capacitors at its input and output (look at the datasheet for this stabilizer and see that the manufacturer STRONGLY requires capacitors ABOUT the stabilizer terminals, which is often violated and when the filter capacitor dries up, the stabilizer often goes into the mode of generating rectangular pulses with an amplitude of up to rated output voltage - self-excited. If so - feel free to change the diode bridge, electrolytes and the stabilizer itself with new ones. True, the comparators may not work correctly, but first check the electronics power supply circuits.
P.S. If you find a link to the Defender scheme - write it down, it will be easier to advise.
P.P.S.Remove the word “Belarusian” on your website and then the phrase will become more correct. For the concept of "social advertising" is delusional by definition. But the discussion of this issue is beyond the scope of the topic.
Sincerely, ALEX.
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 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.
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.
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 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 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.
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.
Resanta voltage stabilizers can be found in many apartments in our country, which is understandable. This is due to the fact that such units make it possible to normalize the operation of all electrical appliances that are present at home. In other words, they allow you to save quite expensive equipment in the event of an overload in the network, or in case of voltage surges, thereby significantly extending the operational life of all electrical equipment.
However, the operation of the voltage stabilizer also carries the risk of certain breakdowns, the only way out of which is timely repair .
There may be several reasons for this - from improper operation to natural causes of breakdown, i.e. long service life.
To avoid this, you must exactly follow the instructions that are included in the kit, which allows you to significantly extend the service life of the unit in the correct mode of operation. If, nevertheless, a breakdown did happen, then you need to know what methods you need to correctly carry out repairs with your own hands, so as not to further aggravate the situation. In this article, we will look at the main malfunctions, as well as ways to eliminate them in a timely manner.
This video shows the Resant's stabilizer with a malfunction
VIDEO
automatic transformer;
the electronic unit;
voltmeter;
a control that is responsible for starting and disconnecting some windings.
This manufacturer produces many different types of stabilizers , therefore, these organs for connecting the windings will differ. We will talk about all these nuances a little later, during the consideration of the repair procedure.
In this design, the decisive factor is the electronic unit, which carries out the general control of the entire system of the unit. He is responsible for the operation of the voltmeter, and also receives information about the power of the input voltage. Then, the block compares the obtained values with the optimal ones, determining the next action, i.e. whether you need to add a few volts or, on the contrary, subtract a certain amount.
Further, along the chain, there is a determination of the necessary windings - which of them need to be started and which ones to be disabled. Then, the electronic unit performs one of these actions, after which all electrical appliances in the apartment receive a stable current.
Of course, the stabilization process itself can be slightly different, depending on the type of device produced.
This difference applies to the types of windings, as well as the methods of starting and disconnecting them. Today, the Resanta company produces two types of these stabilizers:
Electromechanical type.
Relay.
Accordingly, their repair will be somewhat different.
The servo itself consists of a motor on which an electrical contact (brush) is located. When the armature of this motor moves, accordingly, this brush also rotates, constantly contacting with copper windings. The width of this brush allows for a complete wrap-around of the entire winding, which allows the phase not to be lost.
In order for the brush to move in a given direction with the desired characteristics, an error voltage arises in the device. Then, this voltage value rises. Then it is transmitted to the engine, which makes the armature rotate in the optimal direction. Accordingly, the brush also moves, like the armature, in the same predetermined direction. In this case, direct contact with the windings is carried out.
The error voltage value will be proportional to the value formed by the difference between the real voltage value at the input and the value that should be there. This signal can have one of two polarities, each of which specifies a certain direction of movement. Below is a diagram of a similar voltage regulator:
Regardless of the specific model, the structure of this voltage regulator will be almost the same. They differ among themselves by different power values and individual circuit elements.
All relay stabilizers equalize the current values by surges. This is because the relay starts or turns off the turns located on the second winding. An electromechanical stabilizer performs this process more smoothly than a relay one.
Relay units from Resant connect the turns until they find the right one. All these turns are conventionally divided into subgroups, and from each turn there is an output to which the current flows when the device is started.
The diagram of all relay stabilizers of this brand shows that there are about four relay elements in its design. In some cases, this number can be equal to five (SPN models).
In the case of relay stabilizers, it is the relay that is the most vulnerable point of the entire device. This is due to the fact that it is in a constant operating mode, which significantly increases the risk of failure .
Having considered the principles of operation of both types of voltage stabilizers, we can conclude that it is their main components that are the most frequently breaking system components. We are talking about a servo drive in electromechanical devices, as well as relays in relay ones.
In the first case, the constant movement of the servo leads to periodic friction of the turns of the coil and brush, which leads to excessive overheating of these components. It also causes severe wear and tear and sparks from copper wires.
It is also necessary to bear in mind the fact that the current value periodically changes in the network, which provokes a similar change in the movement of the servo. Such unstable operation can lead to the failure of this device.
Repair of one of the faults is demonstrated in the video.
VIDEO
The repair of the Resant's stabilizer can be roughly divided by the type of breakdown.
First, consider the situation when the Resant servo motor has failed. There are two ways out of this problem. :
Buy a new motor, then install it in the device.
Try to repair the damaged one.
While everything is clear with the first case, the second requires detailed consideration. It is important to understand that in case of successful repair work, the restored engine will not be able to work for a long time, i.e. this is a temporary measure.
Everything our actions will boil down to the following:
Disconnect the servo motor from the general structure. Then we connect it to a power source with sufficient power.
It is necessary to supply a current of 5 V to the outputs of the motor. The indicator of the current strength must be at least 90 mA.
The implementation of these manipulations will normalize the operation of the stabilizer. Next, you need to connect the motor back to the circuit.
The circuit is quite simple: the input cable is connected to the input terminal, the neutral cable is connected to the neutral terminal. The same manipulations are performed for the output cables. Also, remember to connect the ground wire.
Failure of the relay is often leads to breakage of transistors ... For example, in the ASN-5000 model, there are D882P transistors. The diagram is shown below:
If these transistors fail, then you need to purchase new ones in their place. You can buy them quite freely, because many specialized stores sell equipment and components of the Resanta brand.
You can also try to repair damaged parts:
First you need to remove the relay cover. Next, we remove the movable contact, freeing it from the spring.
Using sandpaper, we clean off all carbon deposits from the contact. We carry out this manipulation for both contacts - upper and lower.
Then we lubricate the contacts with gasoline, after which we assemble the relay structure.
Another possible problem is the disordered switching on of the display, as well as the switching on of the relay itself. The reason for this may be the XTA1 resonator, which may have an incorrect soldering.
The repair is as follows :
We solder this resonator with a soldering iron.
We clean the leads with sandpaper.
We solder the resonator back.
Specialist's story about Resant's repair
VIDEO
To make diagnostics, we need a LATR device, i.e. laboratory autotransformer of controlled type. We connect the stabilizer to this device, with which you need to change the voltage values. In parallel, we are monitoring the work of the Resant stabilizer.
The implementation of repair work, in this case, can be done at home. At the same time, it is assumed that the person performing these manipulations will be well acquainted with such a technique, have the skills of proper soldering and some knowledge in electronics. If a person does not possess this, then it would be more expedient to turn to specialists.
There are quite a few similar service centers in Moscow and St. Petersburg. In particular, "Demal-Service", located at the address: Moscow, st. 1st Vladimirskaya, house 41.
Video (click to play).
In St. Petersburg there is a service center of the company itself, located at the address: st. Chernyakovsky, house 15.
