DIY receiver repair

In detail: do-it-yourself receiver repair from a real master for the site my.housecope.com.

Let's consider some of the nuances of the repair in more detail. If the receiver works, but not correctly, then at the beginning of the repair, first of all, you should check (or reinstall again) all the necessary software settings of the equipment. If this does not help, we proceed to check the antenna-feeder path - we check the antenna settings (whether it has moved, is there any damage or deformation). Next, we check the converter and the lead-in cable.

The converter can be checked using Satfinder or another receiver - if there is a problem in it, you will have to spend money on buying a new one (although some, especially inquisitive home-builders, manage to cut the internal silumin case of the converter and get to its insides). I would especially like to draw your attention to the choice of an antenna cable - the use of a low-quality (China or Poland) antenna cable of the RG-6U type can lead to very serious consequences.

This cable does not stand up to any criticism - the outer insulation can be torn off by hand, a violation of the insulation at least in one place leads to the fact that the inner sheath of the cable is filled with water! The use of bimetal as a material for the central core leads to corrosion in the first season. As a result of external factors, the cable may fail in a week (there have been cases!) After installation. Professionals in the field of satellite reception will advise you to use a cable from the Italian company Cavel, which is much more expensive than a proven cable from domestic manufacturers, also suitable for use.

The most common malfunction of a satellite receiver is a malfunction of the power supply, as the most unreliable part of any electronic equipment. The power supply generates voltages to power the internal circuitry of the receiver as well as to power the external LNBs and the drive (if installed). We start repairing the power supply unit by checking the fuses and protective breaking resistors. Burning out of these parts does not necessarily indicate a malfunction of the circuit - it may have happened as a result of a surge in the AC mains, or these parts originally had a manufacturing defect. If the malfunction was not eliminated, we begin to "dig" further. To do this, consider the principle of operation of a pulsed power supply unit on a block diagram.

Video (click to play).

The equipment of European manufacturers in this regard is certainly out of competition (in comparison with Chinese) - the simplest receiver shown in the picture (with the cover removed) from the German company Golden Interstar has been working without repair in my dacha for many years. Consider all the above criteria for choosing equipment and you will not have to repair it!

Hello, today we will try to fix the Tricolor receiver. Many faced such a problem when the warranty (usually 12 months) expired and the receiver suddenly failed. A new one is expensive, and in most cases the repair will not be difficult and will cost a penny, if you are even a little friends with a soldering iron, the main and most common faults are easy to fix yourself. Let us consider such a repair using the example of another receiver from the Tricolor company GS-8300 N. It must be said that the device is not of the best quality, and the money that Tricolor takes for it, of course, is not worth it. But, nevertheless, the number of subscribers is large and not all of them work for a long time and regularly.

The main and most common malfunction of all receivers is a malfunction in the power supply and voltage conversion circuit.Also, the modulator often fails due to a short circuit in the coaxial cable from the LNB, although the latest models have good protection against short circuits in the cable, when triggered, the voltage supply to the converter simply stops until the short circuit is eliminated.

And so, our receiver does not show any signs of life, the indicators on the front panel display do not light up, and no twitching of the power plug from the outlet and turning on the toggle switch does not help us (at least that was the case with the device, an example of which is given in this article) ... The first thing we do is pull out the plug from the network and remove the top cover, we need to get to the electronic filling of the device. And here it is important to remember one thing, namely, about the warranty seal, which of course we will break if we remove the cover. Therefore, once again make sure that the warranty period has definitely expired, and under warranty no one will repair it for you. If the warranty is still valid, I advise you to take the receiver to a service center and entrust this matter to a specialist.

Receiver inside:

The electrolytic or oxide capacitor at the input often dries up and fails, which is also a malfunction, not everyone can find such a breakdown either, you need to have at least an initial level of a radio amateur. Usually, defective capacitors are swollen, yellowish, or have a small brown speck on the board at the base of the legs. Also, the serviceability of a capacitor can be determined by comparing its nominal and measured capacitance.

The receiver uses direct current, which is rectified from the AC mains using a diode bridge. Problems with the diode bridge also happen. It is very simple to check diodes, the main function of a semiconductor diode is to pass current in one direction, and not in the other. In my case, the transistor of the primary winding of the transformer turned out to be faulty, it is not difficult to find it, it usually has a radiator to remove heat. I determined the malfunction of the transistor by measuring the voltage at its emitter, it was absent there, the primary winding was not powered, respectively, everything else is de-energized. The transistor cost me 28.5 rubles. Replacing it with a soldering iron, I eliminated the malfunction and the receiver is back in working order. I must say such a breakdown is quite a rare occurrence, usually it all ends with a fuse.

A very common malfunction is a firmware crash. The firmware often crashes, this is usually evidenced by the complete hang of the receiver. In this case, "flashing" will help. I will tell you about one more reason for the malfunction, which may arise due to poor-quality installation. Water in the cable. If the outer insulation of the cable is broken, then water from atmospheric precipitation can get inside, it easily enters the receiver like a hose, sometimes flooding all of its insides. The condition of the cable must be monitored throughout the entire service life of the device.

In this article, we will fix the most common breakdown in a satellite receiver, namely, we will repair the power supply of this device. Why a power supply? Yes, because in 95% of cases of failure of the receiver, the power supply is the culprit. The receiver may not turn on at all, it may turn on "halfway" (for example: the red indicator is on, and the green one, despite our efforts when pressing a certain button, does not turn on and there are many more signs), or some function may not work. And the reason for all these misunderstandings, in most cases, can be the power supply. We will repair the SVEC receiver, but functionally, on most of these devices, the power supplies differ only in the shape and location of the radio elements. The principle of repairing receivers is almost always the same.

So, let's begin. To begin with, of course, you need to disassemble our "unit". We unscrew the screws or bolts on the sides of the cover and remove it. We are presented with the following picture:

Now we will visually inspect the unit and the board for the visible reasons for the breakdown (this can be "swelling" of capacitors, burnout of the board or individual elements, etc.). If no apparent reason is found, then we look at the fuse. Even if it is not visually visible that the fuse has "blown", it is better, nevertheless, to check its integrity with a device. If the fuse is not working, do not rush to change it and try to turn on the receiver. Usually they just do not "burn out", on the contrary, for the most part, with overvoltage in the network, they remain unharmed, and something else must fail. This is how modern technology works. In general, we need to remove the power supply (in the figure it is marked with a blue arrow) from the receiver in order to check other items.

First of all, you need to check the power capacitor: there may be a residual charge in it. If there is a charge in the capacitor, it is imperative to discharge it, otherwise, when checking other radioelements, we can not only "burn" the device, but also get a good electric shock, albeit not fatal, but still unpleasant.

After that, we proceed to check the main transistor, which stands on the radiator. If we discard all professional terms, then we simply "ring" him for a "short circuit". These transistors are constantly failing, they are designated like this: D13009K. The literal values can be different, but the numerical values must be the same. This transistor is found in many receivers, but not all. In others, there are similar ones or there may be microcircuits. This is not the point, it is important that in most cases, it is the power transistors or microcircuits that fail.

On our power supply, after checking this transistor, a short circuit was found between its contacts. It follows from this that the transistor is "burnt out".

Now we need to unsolder it and check the rest of the radioelements. I will explain the check in a simple way: you need to check all the transistors and diodes (zener diodes) for a "short circuit".

All parts marked with arrows in the picture must be checked for "short circuit". After such a check, I found a "burnt out" diode, which is powered by 5V. We also need to remove it, so that, like the transistor, we can replace it with a usable one.

Next, we solder the new transistor and diode into place. Then you can check our power supply. We do it like this: insert it into the receiver and connect only the power cord and the power button to it. We DO NOT connect the loop with wires that goes to the board with processors. We will check by the output voltages, the value of which is indicated on the power supply, near the "socket" where the loop is inserted.

We measure the voltages at the output of the power supply and, if they coincide with the values on the board, you can connect a loop.

Everything. Now we fasten all the bolts that secure the power supply to the receiver and close our device with a lid. Ready.

Of course, the most common and not difficult type of breakdown is described here. There may be more serious reasons for the failure of this device. Then, without the intervention of a specialist, it is impossible to do, but without doing anything, it is impossible to learn something.

Thank you. Very interesting article. Everything is clear and simple.

Thank you for your feedback and participation in the life of the site!

Hello, I have such a problem, the receiver turns on, but when the cable is connected from the WORKING antenna, there is no signal or quality. I opened the receiver. Not one condenser is swollen, what could be the problem?

I only repair power supplies in receivers, but I don’t climb into the main board, so I can’t help. But I can assume that this is a tuner or firmware.

Hello Victor, I have such a problem. I got the same svec A8 receiver as a gift. The power supply unit was not in working order. The D13009k transistor failed, I replaced it with J13009k and the power supply unit came to life, but it turned out that the U5 transistor was missing on the main board. Could you please write and photograph its marking. I would be very grateful for your help.

Hey! U5 is an LM317 regulator, the same as U24.

Hey! Thank you so much for your reply. And then I climbed the whole Internet and did not find a scheme from him. I will solder and try to run.

Hello. Globo 4100c the red indicator flashes when the button is pressed up lights up 8. Visually, everything is in order in the power supply unit. What should be changed first in it?

Hey! Check the output voltages from the power supply, the stabilizers on the main board.

Hello. There is an Orton 4050c tuner. After disconnecting from the network, it did not start. The display shows a flashing red light and flashing numbers. Having disassembled, I did not find any swollen canders. But I found out a bad soldering (something was wobbling, something just fell off when I touched it) Soldered. I measured the output voltages on the removed BC. There is. 3.3v. 5v. 12v. 22v. True, my DT-832 tester shows slightly overestimated readings (3.5v 5.5v 14.3v 24.2v). But when connected to the board, 3.3v and 5v disappear. The display turned off. The same. I can't figure out where to dig. Can anyone help. Thanks in advance.

Hey! Look at the stabilizers on the main board.

Zdrastvujte.pomagite pocinit resiver VU SOLO 2SE posle grozi nevkliucajetse.bp pocinil.kogda nazimaju na knopku vkliucenija na resivere lampa nemnogo jarce svetitse otpuska mozu opju shezet jarce svetitse otpuska mozu opju shezet jarce svetitse otpuska mozu opju shezet jarce svetitse otpuska mozu opju shezet jarce u.

After a thunderstorm, the processor usually crashes or the firmware flies.

na usb portah net 5 volt.prosit nepolucajetse.

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Satellite TV is evolving with every update and with every new device. Every satellite TV user from time to time encounters problems and errors in the robot of his receivers or other components. This can be due to various factors. For example, older models may fail due to long operating times. Despite their quality and reliability, devices can break down due to unsatisfactory weather conditions, electrical problems or improper use. Let's take a closer look at this.

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Among the reasons for the breakdowns of the GS8306, GS8300, DRS-5001 models are the following:

the receiver does not start;
the timer flashes on the display of the set-top box at startup;
on the display of the prefix only a non-blinking timer;
on the display of the prefix the inscription "boot";
on the display of the prefix error message ER31;
an error on the TV display when switching on "Short circuit!" or "Check antenna cable".

In the case of the last error, you can carry out diagnostics yourself to clarify the cause of the malfunction. When the wire was disconnected, the error message disappeared, the problem is with the satellite converter or the antenna cable. Next, you need to check the wire in case of a short circuit. If it is not there, there is an error in the satellite converter. But, if the TV still signals an error, the problem is in the tuner.

These types of breakdowns include other representatives of the series of MPEG-2, MPEG-4 and Full HD set-top boxes. There is no need to prematurely go to the store for another device, because the purchase will definitely cost a lot. It is recommended to contact service center for qualified help, or repair the receiver with your own hands, if you have the necessary skills.

Diagnostics show that often the components of the set-top box fail:

firmware - this can be detected if you see errors on the display;
receiver power supply Tricolor - when the receiver does not turn on or the timer is flashing;
motherboard - only timer is displayed or in case of error ER

However, satellite TV users may encounter picture, sound or signal problems. This also happens due to problems with the receiver. The following are attributed:

breakdown of the satellite converter;
the antenna cable is damaged;
breakdown of the tuner unit;
weak signal due to obscuring trees;
unsatisfactory weather conditions.

The reasons also include channel broadcasting frequency change or even a whole package of channels or satellite malfunctions, to which the service center has nothing to do.

First of all, you do not need to start repairing Tricolor receivers yourself if you are 100% not sure what and how you are doing. If the warranty period is valid, it is best to entrust the repair of the Tricolor satellite receiver to a specialist.But, this is possible if there is a warranty card, purchase receipt, client's signature. The repair warranty may be voided if:

operation of the receiver during power surges;
damage to the seal or the integrity of the structure;
mistakes when switching, connecting cables or incorrect programming;
the receiver was not installed by an installer, and this led to a breakdown during operation;
the client has violated the terms of use;

All this must be adhered to if the client wishes to repair his receiver in the future.

Repair of the Tricolor TV receiver is as follows:

replacing the motherboard;
changing the power supply;
replacement of the module;
flashing or reinstalling software.

If the motherboard breaks down, it is most often recommended to buy a new and more modern version of the set-top box, because repairing the motherboard will cost almost at the price of a new receiver.

For example, there are a number of errors typical for each type of device and options for correcting. The peculiarity of the repair of the GS8300 receivers of the Tricolor company depends on the alteration of the power supplies, because the devices are not highly resistant to voltage surges. Overheating was a typical problem for the GS 7300, causing the diode bridge or chip to break. Also, the power supplies for the Tricolor receivers sparked after prolonged operation, so they often had to be changed. The most optimal model, the GS8306, also had typical problems. For example, overheating during prolonged viewing of channels.

Satellite TV is not the last in the entertainment industry. And this is facilitated by the inexpensive price of equipment and an extensive list of channels. But all the joy can descend to "no" if the satellite TV receiver does not turn on. Image - DIY Receiver Repair

All is good, but there is one unpleasant moment. Chinese receivers often fail. The main reason for equipment failure is a breakdown of the power supply. This happens due to thunderstorms, voltage surges, and simply poor-quality components of this unit. In contrast, other receiver modules practically do not break. It is about this common breakdown that we will talk about and find out how to repair the receiver's power supply with our own hands.

This article will provide simple and practical ways to identify a faulty part in a tuner power supply. Although the methods are simple, their use in most cases allows you to repair the power supply of a satellite TV receiver with your own hands.

So, if your satellite TV receiver of the model: Gione, Cosmo Sat and the like has stopped working, then do not rush to worry, perhaps everything is not so bad. Try to find the cause yourself without the help of specialists.

What might you need? Multimeter, dial tone, soldering iron and a little patience.

We remove the cover of the device, and we see a free-standing module. This is a switching power supply. To start troubleshooting, remove it by unscrewing the screws and disconnecting the connector on the system board. Now the board is in front of us.

The first thing to do with the board is to visually determine if there are damaged (swollen) capacitors and other circuit elements. Often it is for this reason that the satellite TV receiver does not turn on.

If no damage is visible, then it is necessary to check the integrity of the cord and fuse. We put a dial on the ends of the fuse, and by the reaction of the device we determine its integrity.

If the fuse is good, that's good. And if not, then you should not rush to change it, since the same thing can happen to it as to the first one. It is better to solder a cartridge with an incandescent lamp in its place. A lamp with a power of 60 watts and a voltage of 220 volts.

Now, if in the circuit, when turned on, there is a short circuit, then the lamp will simply light up at full heat, without causing any harm to the circuit. If the lamp does not light up when turned on, we take a multimeter and measure the voltage across a large capacitor of 47 μF * 400 volts.

The multimeter must be set to the "DC voltage measurement" mode.At the contacts of the capacitor during normal operation, there should be a voltage of about 300 volts. If there is none, then we are calling along the chain - from the fuse to the diode bridge. In the case of the presence of an alternating voltage at the input of the bridge, everything indicates a breakdown of the diodes, and this is also one of the frequent breakdowns in which the satellite TV receiver does not turn on. To determine which diode is out of order, it is necessary to solder one end of each.

Then, throwing a dial on each diode alternately, and swapping the ends, we determine their integrity. The working diode must pass current in one direction. If the diode rings in two positions in the same way, then it is broken. Most often, a pair of diodes fails. Therefore, if possible, it is better to change all four at once, since after such breakdowns, even those that remain workers change their parameters. As a result, partial replacement of diodes can be considered as defective repair of the receiver's power supply. And this means that there is a high probability that at one fine moment you may again face a situation when it is necessary to eliminate this malfunction, as a result of which the satellite television receiver stopped working.

The diodes have been replaced, now we turn it on again and measure the constant voltage across the same capacitor. It should be, as mentioned above, about 300 volts. If so, then the next step in the diagnosis is to measure the alternating voltage on one of the primary windings of the transformer. How to do this can be seen in the photo below.

The device should show about 150 volts, and the voltage should seem to "float", that is, change. If this does not happen, then most likely the microcircuit is out of order. You can replace the microcircuit and repeat the measurements again.

When the device shows the presence of a pulsating AC voltage on the primary winding, it is necessary to immediately measure the DC voltage at the output of the unit.

To do this, put the multimeter in the "constant voltage measurement" mode and connect the negative (black) probe to the second slot on the connector. This is a common (negative) contact. With the other end of the device, we alternately measure the voltage at the slots of the connector.

If you turn the plug with the slots towards you, and measure from left to right, then the voltages should be as follows:

If there is no voltage, then we do the same operation with the diodes of the secondary circuit, as described above. Having identified the faulty one, we replace it. Note the larger diode. It is labeled SR-360 and the like. He most often fails. Replacing it, you can solve the problem when the satellite TV receiver does not turn on. Again we measure the voltages at the terminals.

If this method did not give anything, then most likely the microcircuit in the primary circuit, which plays the role of a high-frequency alternating voltage generator, "flew out". But, as practice shows, this rarely happens.

That's all that I wanted to tell you about the repair of the power supply unit of the satellite TV receiver. Successful renovation.

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Written by Administrator on 07 December 2011.

Hello, today we will try to fix the Tricolor TV receiver with our own hands. Many faced such a problem when the warranty (usually 12 months) expired and the receiver suddenly failed. A new one is expensive, and in most cases the repair will not be difficult and will cost a penny, if you are even a little friends with a soldering iron, the main and most common faults are easy to fix yourself. Let's consider such a repair using the example of another GS-8300 N receiver from the Tricolor TV company. I must say that the device is not of the best quality, and of course, Tricolor TV is not worth the money that Tricolor TV takes for it. But, nevertheless, the number of subscribers is large and not all of them work for a long time and regularly.

And so, our receiver does not show any signs of life, the indicators on the front panel display do not light up, and no twitching of the power plug from the outlet and turning on the toggle switch does not help us (at least that was the case with the device, an example of which is given in this article) ... The first thing we do is pull out the plug from the network and remove the top cover, we need to get to the electronic filling of the device. And here it is important to remember one thing, namely about the warranty seal, which we will of course break if we remove the cover. Therefore, once again make sure that the warranty period has definitely expired, and under warranty no one will repair it for you. If the warranty is still valid, I advise you to take the receiver to a service center and entrust this matter to a specialist.

The electrolytic or oxide capacitor at the input often dries up and fails, which is also a malfunction, not everyone can find such a breakdown either, you need to have at least an initial level of a radio amateur. Usually, defective capacitors have a yellowish appearance, or a small brown speck on the board at the base of the legs. Also, the serviceability of a capacitor can be determined by comparing its nominal and measured capacitance.

A very common malfunction is a firmware crash. The firmware often crashes, this is usually evidenced by the complete hang of the receiver. In this case, "flashing" will help. I also want to say about another cause of the malfunction, which may arise due to poor-quality installation. Water in the cable. If the outer insulation of the cable is broken, then water from atmospheric precipitation can get inside and it easily enters the receiver like a hose, sometimes flooding all of its insides. The condition of the cable must be monitored throughout the entire service life of the device.

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Electronic devices surround us everywhere: on the street, at work, at home. With the rapid growth and availability of satellite television to the general public, a wide range of satellite equipment has emerged for the general public. These are satellite receivers, conditional access modules, antennas, converters, etc. Whether we like it or not, sooner or later breakdowns occur with them, which cause us to feel the loss of our beloved thing.

You should not despair - for this there are service centers that you can turn to and they will help you to bring your equipment back to life.

Breakdowns of equipment occur for various reasons - voltage drops, failure of various nodes, wear and tear of the equipment itself from its venerable age, you can also note the incompetence of the owners themselves, for example, improper replacement of software in satellite and cable receivers.

Power supply failure is perhaps the most common type of digital terminal failure. It arises for various reasons: a poor-quality supply network (see photo), poor-quality radio components were used, especially this is de facto in Chinese technology.

Also, this can include violation of operation, dust, dirt, as a result of this, the thermal regime is not correct (see photo).

A service center is a structural unit within a company. He is responsible not only for the repair and maintenance of the products sold by our company, but also for the repair (including warranty) of satellite equipment from other companies. Our clients are not only individuals - users, but also equipment dealers who seek to save their customers from the problems associated with the repair and maintenance of receivers. Our flexible corporate customer policy allows us to provide adequate service and meet the interests of all customer groups. This is more than 1000 units of equipment per month. To carry out such large volumes, of course, allows the professionalism of the staff, the equipment of the service center with professional equipment, tools and technical documentation. Therefore, in our service center we carry out high-complexity repairs: for example, replacing processors in BGA cases. Repair takes place in the shortest possible time.

The supply department, in addition to its main function - the purchase of equipment, is also engaged in meeting the needs of the service center, purchasing components necessary for repair. And here it is worth noting that the selection and purchase of components for repair is carried out according to the following criterion: the quality of parts comes first, their price comes second, but due to the large volumes of supplies of parts, the price ultimately remains low.
All orders are processed electronically and registered in the database. This makes it easy to track the various stages of the repair process. A guarantee is provided for the work performed.

Of course, unforeseen moments happen - for some reason, the repair is delayed. This usually happens due to the lack of some scarce radio component. Sometimes repairs require a complete replacement of the motherboard, and this repair part is not always available. In this case, we are trying to find some acceptable solution together with the client, taking into account his wishes, combined with our capabilities.

At autopsy, found out of order:
- network capacity C5 - 47µFx400V
- Q1 - CS2N60F
- R8, R11, R13 - each with a nominal value of 3 Om (frame size 1206)
- R9 - 47 Om (1206)
- U1 - it was not possible to determine its type by the marking on the case.

According to the table on identification and selection of analogs https://my.housecope.com/wp-content/uploads/ext/2561/ic_power/, the last part was replaced with SG6848 with minimal interference with the factory circuit.
Dismantling: (circled in red in the photo)
- U1
- R8, R11, R13 - 3 Om (1206)
- R3, R6 (one of them is possible) - 1 MOm (1206)
- C3 - 68nF
- R25 - 3.6 kOm (0805)
- R26 - 10 kOm (0805)
Install:
- instead of U1 - SG6848
- instead of R8, R11, R13 - one 1.8 Om x 0.5W resistor (the usual output one, since I did not find the smd of the required rating))
- instead of C3 a 100 kOm resistor (1206)
- instead of R26 a 33 kOm resistor
- instead of R25, we select a resistor in the range of 10-12 kOm, monitoring the voltage 3V3 at the cathode VD8. I settled on the nominal 11 kOm, U = 3.36V (at 10 kOm U = 3.28V, at 12 kOm U = 3.41V)

SSS4N60B (TO-220F package) was installed instead of the burnt-out Q1

On Telesputnik posted a diagram of the power supply unit.

There are inaccuracies:
1. The lower terminal of the primary winding must be connected
to the junction point of the anode D6 and drain Q1
2. Positional designations C2 and C3 are incorrect. C3 must be connected to the 3rd pin
U1, C2 to the 4th pin of U1.
3. Nominal C3 = 68nF
4. In the diagram, there are two capacitors C1
5. Missing C12
6. The primary land is designated in the same way as the secondary one.
7. Missing C8
8.Q2 - MOSFET NTD14N03R
9.Rated C11 = 2200pF
10. Type D8 = SR560
11. Positional designations U3 and U4 are incorrect - they must be reversed.
12. Denomination C5 = 47µF

The receiver turns on, the LNB has 18 volts. There is no video signal, it gets very hot (the finger does not hold) stv 6419 .. because of it there can be no video? there is no other point? (in the sense that there is no other source of video signal?) The receiver switches channels ..

Receiver GS 8300N there is no video and audio signal through scart to the TV, the channels are switched on the receiver panel.

the video signal from the STi5119ALC chip can be checked with an oscilloscope at the control point opposite the capacitor C117, then it comes to the resistor R87 and is transmitted to the capacitor C129 and then goes to the STV6419 microcircuit from it there is no output to R91, the culprit is not 12 volts on the board, respectively, there is no power + 12V on the 3rd leg STV6419, a 12 volt Zener diode D3 is faulty near the power connector

There was such an answer: if you use only composite video signal, most likely it can be simply thrown out (replaced with a jumper). And where to put the jumper? if that's the right advice ..

Defective VD3 (VD3 zener diode 12 V) on the motherboard next to the power connector.

Zener diode brand and parameters:

Power supply + 12V for 3rd leg STV6419.
Along the chain: XP5 connector 9th leg -> R81 (300 Om) + Zener diode VD3 (12V) = stabilizer + 12V -> L3 -> 3rd leg STV6419.

Zener diode analog:

VD3 STV6419 similar Zener diode (SMD) did not find. Put a 0.5 watt glass zener diode the size of a diode kd522 ... While the flight is normal.

If replacing the zener diode did not help:

After the thunderstorm, 6419 swelled. After the replacement, the image did not appear, but when checking the strapping, two resistors were cut off, R91, R95... I replaced it, and it worked.

One more problem:

And yet, instead of 13, 18 Volts, 24V was running on the LNB. Replacement required DA1 (LM317T)... And that's it, the flight is normal

The same situation with the GS-8304 receiver:

After 5 years of operation, the GS-8304 suddenly stopped broadcasting, although the indication is working properly.
Zener diode struck at short circuit. Zener diode brand MMZE5242B.

Hello guests and blog readers! Almost every inhabitant now has a satellite dish. And the problem of failure of its elements, such as a converter, a receiver and an antenna feeder, does not bypass it. In this article, we are with you and we will try to consider the main malfunctions of satellite dishes.

Repair of satellite receivers is done much more often than converters. This is due to the low quality of receivers made in China.
The main reasons for receiver breakdown are drying out of electrolytic capacitors, converter breakdown, damage and atmospheric precipitation into the antenna-feeder system (cable), damage to the receiver's firmware and failure of the receiver's power supply as a result of a voltage surge, etc.
What are the nuances of repairing satellite receivers? If the receiver works, but "glitches", then first you need to check and, if necessary, reinstall its software settings. If this does not help, you need to check the antenna-feeder system (whether the antenna has moved). Then next you need to check the converter and the cable connecting it to the receiver. It is better to install a converter that is known to be working properly for checking.

I would like to focus on the quality of the cable used in satellite dishes. This should be given special attention, since the use of a low-quality cable often leads to serious consequences.
If the outer sheath of the cable is damaged, the inner one is filled with water. And this, in turn, causes corrosion of the inner core and quick damage to the cable. Therefore, I do not recommend installing a cheap Chinese cable.
You can check the cable with a simple multimeter. And if, after all these checks, no image appears on your TV screen, then go to the main element of the satellite dish - the receiver.

Very often the reason for the malfunction of the satellite receiver is the firmware “crash”. In this case, only its flashing will help. This is where you need a null modem cable, bootloader, software, and experience with receiver firmware. If you do not have such experience, then entrust this business to professionals. Otherwise, you can completely ruin your receiver and it will be very difficult to restore it.

Consider some common receiver malfunctions, or rather a power supply malfunction.
The power supply is the most unreliable element of any electronic circuit.The durability of the entire electronic filling of the receiver depends on the stability and magnitude of the supply voltage.
And so we will start repairing the power supply by checking the fuse and protective resistors.
Protective resistors burn out for a reason. The main reason is overload and surges in the mains voltage. If, after installing serviceable parts, the power supply did not function, then we move on.
In the switching power supply, the mains voltage is rectified and supplied to power the converter and the power controller. The converter converts the rectified voltage into high frequency current and supplies it to the transformer. The transformer winding has several parts. One part is used for control. The PWM controller measures the voltage across it and changes the duty cycle and frequency of the pulses supplied to the primary winding of the transformer. This ensures that a stable output voltage is maintained.

In a switching power supply, control is also carried out for the supply voltage of the receiver's digital circuit (processor and memory).
The voltage to the PWM controller is supplied through an optocoupler. This makes it possible to carry out galvanic isolation from the high-voltage part of the circuit.

From the additional and main secondary windings, the voltage is supplied to the rectifiers and stabilizers.
Voltages from 24 to 33 volts are required to supply bias to the high frequency tuner's varicaps.
A voltage of 12 volts is supplied to power the analog part of the receiver circuit (sound and video).
Voltages of 5 and 3.3 volts are required to power the digital microcircuits of the receiver.

Troubleshooting should begin by checking the diodes in the high-voltage part of the switching power supply circuit and in the low-voltage one. Also check the resistors for open circuit and the condition of the capacitors. If they are torn and swollen, they must be replaced immediately. Electrolytic capacitors dry out quickly and lose their rated capacity. And this leads to the inoperability of the electrical circuit as a whole.
Check voltage regulators and Schottky diodes.
When you test the diodes with a digital multimeter, they may be intact, but have a leakage current. This is unacceptable and often leads to malfunctions. Keep this in mind.

Video (click to play).

If the troubleshooting was not successful, then you should pay attention to the PWM controller and its piping circuit. Replacing it (microcircuits) often brings the receiver back to life. Check the winding of the transformer and chokes for an open.
Another reason for the malfunction may lie in the lack of contact legs of the transformer of the switching power supply. Sometimes you can't see it with the naked eye, so use a magnifying glass. Be sure to solder all suspicious places. Repairing a satellite receiver can take a very long time, but after repair you will gain experience.
And also, what I would like to say. Don't buy suspiciously cheap satellite receivers. You can run into a fake that will not work for a month. Good luck with the renovation and goodbye!

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DIY receiver repair

So, let's begin. To begin with, of course, you need to disassemble our "unit". We unscrew the screws or bolts on the sides of the cover and remove it. We are presented with the following picture:

On our power supply, after checking this transistor, a short circuit was found between its contacts. It follows from this that the transistor is "burnt out".

Now we need to unsolder it and check the rest of the radioelements. I will explain the check in a simple way: you need to check all the transistors and diodes (zener diodes) for a "short circuit".

All parts marked with arrows in the picture must be checked for "short circuit". After such a check, I found a "burnt out" diode, which is powered by 5V. We also need to remove it, so that, like the transistor, we can replace it with a usable one.

We measure the voltages at the output of the power supply and, if they coincide with the values on the board, you can connect a loop.

Everything. Now we fasten all the bolts that secure the power supply to the receiver and close our device with a lid. Ready.

Of course, the most common and not difficult type of breakdown is described here. There may be more serious reasons for the failure of this device. Then, without the intervention of a specialist, it is impossible to do, but without doing anything, it is impossible to learn something.

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So, let's begin. To begin with, of course, you need to disassemble our "unit". We unscrew the screws or bolts on the sides of the cover and remove it. We are presented with the following picture:

On our power supply, after checking this transistor, a short circuit was found between its contacts. It follows from this that the transistor is "burnt out".

Now we need to unsolder it and check the rest of the radioelements. I will explain the check in a simple way: you need to check all the transistors and diodes (zener diodes) for a "short circuit".

All parts marked with arrows in the picture must be checked for "short circuit". After such a check, I found a "burnt out" diode, which is powered by 5V. We also need to remove it, so that, like the transistor, we can replace it with a usable one.

We measure the voltages at the output of the power supply and, if they coincide with the values ​​on the board, you can connect a loop.

Everything. Now we fasten all the bolts that secure the power supply to the receiver and close our device with a lid. Ready.

Of course, the most common and not difficult type of breakdown is described here. There may be more serious reasons for the failure of this device. Then, without the intervention of a specialist, it is impossible to do, but without doing anything, it is impossible to learn something.

Popular

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We measure the voltages at the output of the power supply and, if they coincide with the values on the board, you can connect a loop.