Do-it-yourself receiver repair

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

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 for the equipment. If this does not help, we proceed to check the antenna-feeder path - we check the antenna settings (if it has moved, if there are any damages or deformations). Next, check the converter and the supply cable.

The converter can be checked using Satfinder or another receiver - if there is a problem in it, then you will have to spend money on buying a new one (although some, especially inquisitive DIYers, manage to cut the inner silumin case of the converter and get to its insides). I would especially like to focus on the choice of an antenna cable - the use of 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 criticism - the outer insulation can be torn off by hand, the 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 the material of 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 an order of magnitude more expensive than a proven cable from domestic manufacturers, which is 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 receiver's internal circuitry, as well as to power the external LNBs and the motor drive (if installed). We start repairing the PSU by checking the fuses and protective breaking resistors. The burnout of these parts does not necessarily indicate a malfunction of the circuit - perhaps this was the result of a surge in the AC mains, or these parts originally had a manufacturing defect. If the problem could not be 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, of course, is beyond competition (compared to the Chinese one) - the simplest receiver shown in the picture (with the cover removed) from the German company Golden Interstar has been working in my country house for many years without repair. 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 it is 12 months) ended, and the receiver suddenly failed. A new one is expensive, and in most cases, repairs will not be difficult and will cost a penny, if you are at least a little friends with a soldering iron, the main and most common malfunctions can be easily fixed by yourself. Consider such a repair using the example of another receiver from the Tricolor company GS-8300 N. I must say that the device is not of the best quality, and of course, the money that Tricolor takes for it is not worth it. But, nevertheless, the number of subscribers is large and not all of them work for a long time and properly.

The main and most common malfunction of all receivers is a malfunction in the power supply circuit and voltage conversion.Also, the modulator often fails due to a short circuit in the coaxial cable from the LNB, although the latest models have good cable short circuit protection, 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 juggling of the mains plug from the outlet and turning the toggle switch on and off does not help us (at least, this 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 the warranty seal, which we will certainly break if we remove the cover. Therefore, once again make sure that the warranty period has exactly expired, and no one will repair it for you under warranty. 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:

An 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 the initial level of a radio amateur. Usually failed capacitors are swollen, 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.

The receiver uses direct current, which is rectified from the AC network using a diode bridge. Problems with the diode bridge also happen. Diodes are very easy to check, the main function of a semiconductor diode is to pass current in one direction, but 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, usually it has a radiator for heat removal. 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. By replacing it with a soldering iron, I fixed the problem and the receiver is back in working order. I must say such a breakdown is quite rare, usually everything ends with a fuse.

A very common malfunction is a firmware rally. The firmware often flies, the evidence of this is usually the complete freezing of the receiver. In this case, "flashing" will help. I’ll tell you about another reason for the malfunction, which may occur due to poor-quality installation. Water in cable. If the outer insulation of the cable is broken, then water from atmospheric precipitation can get inside; it easily gets into the receiver through a hose, sometimes flooding all its insides. The condition of the cable must be monitored throughout the life of the device.

In this article, we will fix the most common failure 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 culprit is the power supply. 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 a certain button is pressed, does not turn on and there are still a lot of signs), or some function may not work. And the cause of all these misunderstandings, in most cases, may 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. Here is the picture before us:

Now let's visually inspect the unit and the board, for visible causes of failure (this can be a "bloating" of capacitors, burning out of the board or individual elements, etc.). If there are no visible reasons, then we look at the fuse. Even if it is not visually visible that the fuse has “burned out”, it is better, nevertheless, to check its integrity with the device. If the fuse is not working, do not rush to change it and try to turn on the receiver. Usually they don’t “burn out” just like that, on the contrary, for the most part, when there is an overvoltage in the network, they remain unharmed, and something else will definitely 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 elements.

First of all, you need to check the power capacitor: it may have a residual charge. If there is a charge in the capacitor, it is imperative to discharge it, otherwise, when checking other radio elements, 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 is on the radiator. If we discard all professional terms, then we simply “call” it for a “short circuit”. These transistors constantly fail, are designated as follows: D13009K. The literal values can be different, but the numeric values must match. This transistor is in many receivers, but not all. Others have similar or may have microcircuits. This is not the point, it is important that in most cases it is power transistors or microcircuits that fail.

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

Now we need to unsolder it and check the rest of the radio elements. I’ll explain the check in a simple way: you need to check all transistors and diodes (zener diodes) for a “short circuit”.

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

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

We measure the voltage at the output of the power supply and, if they match the values on the board, you can connect the cable.

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 complicated 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, one cannot do without doing anything, it is impossible to learn anything.

Thanks. 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 you connect the cable from the WORKING antenna, there is no signal or quality. I opened the receiver. One conder is not 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 the same problem. I got the same receiver svec A8 as a gift. Was in a non-working state of the PSU. The transistor D13009k failed, I replaced it with J13009k and the PSU came to life, but it turned out that there was no U5 transistor on the main board. Could you write and photograph its markings. I will be very grateful for your help.

Hey! U5 is the LM317 stabilizer, same as U24.

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

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

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

Hello. There is an Orton 4050c tuner. After turning off the network, it did not start. The display shows a flashing red light and flashing numbers. Having disassembled, I did not find swollen kanders. But I found a bad soldering (something staggered, something just touched falls off) 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 not understand where to dig. Maybe someone will help. Thanks in advance.

Hey! Look at the stabilizers on the main board.

Zdrastvujte.pomagite pocinit receiver VU SOLO 2SE posle grozi nevkliucajetse.bp

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

na usb portah net 5 volt.prosit nepolucajetse.

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Satellite TV is evolving with every update and with every new device. Each user of satellite television from time to time encounters problems and errors in the operation of their receivers or other components. This may be due to various factors. For example, older models may fail due to a long operating time. Despite their quality and reliability, devices can break down due to unsatisfactory weather conditions, electrical problems or misuse. Let's consider this in more detail.

Among the causes of breakdowns of models GS8306, GS8300, DRS-5001 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 set-top box there is only a non-flashing timer;
on the display of the console is the inscription "boot";
on the display of the set-top box there is an inscription of the error ER31;
on the TV display an error when you turn 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 inscription disappeared, the problem of the malfunction lies in 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 MPEG-2, MPEG-4 and Full HD set-top box series. 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 shows that often the accessories of the set-top box fail:

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

However, satellite TV users may experience picture, sound or signal problems. This also happens due to problems with the receiver. They include the following:

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

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

First of all, you don’t need to start repairing Tricolor receivers yourself if you are not 100% 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, customer's signature. The repair warranty may be voided if:

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

All this must be followed if the client wants to repair his receiver in the future.

Repair of the Tricolor TV receiver is as follows:

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

In the event of a motherboard failure, it is most often recommended to buy a new and more modern version of the set-top box, because repairing the board will cost almost the price of a new receiver.

For example, there are a number of errors and correction options typical for each type of device. The peculiarity of the repair of Tricolor GS8300 receivers depends on the alteration of the power supplies, because the devices are not highly resistant to voltage surges. For the GS 7300, a typical problem was overheating, which caused the diode bridge or microcircuit to break. Also, the power supplies for the Tricolor receivers sparked after long work, so they often had to be changed. The most optimal model GS8306 also had typical problems. For example, overheating when watching channels for a long time.

Satellite TV occupies not the last place in the field of entertainment. 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 - Do-it-yourself receiver repair

Everything would be fine, but there is one unpleasant moment. Chinese receivers often fail. The main cause of equipment failure is a power supply failure. This happens due to thunderstorms, power surges, and simply low-quality components of this unit. In contrast, other receiver modules practically do not break. It is about this common breakdown that we will talk and find out how to repair the power supply of the receiver with your 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, using them in most cases allows you to repair the power supply of the satellite TV receiver with your own hands.

So, if your satellite TV receiver of the model has stopped working: Gione, Cosmo Sat and the like, 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 be needed? Multimeter, dialer, soldering iron and a little patience.

We remove the cover of the device, and we see a separate 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 payment is in front of us.

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

If damage is not visible, then it is necessary to check the integrity of the cord and fuse. We throw a continuity 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 there is a short circuit in the circuit, when turned on, the lamp will simply light up at full intensity, without causing any harm to the circuit.If, when turned on, the lamp does not light up, we take a multimeter and measure the voltage across a large capacitor 47 uF * 400 volts.

The multimeter must be set to the “DC voltage measurement” mode. On the capacitor contacts during normal operation, there should be a voltage of about 300 volts. If there is none, then we call 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, you need to solder one end of each.

Then, alternately throwing a continuity on each diode, and swapping the ends, we determine their integrity. A 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 working change their parameters. As a result, a partial replacement of diodes can be considered as an inferior repair of the receiver's power supply. And this means that there is a high probability that at one fine moment you may again encounter a situation where you need to eliminate this malfunction, as a result of which the satellite TV receiver stopped working.

The diodes have been replaced, now we turn it on again and measure the constant voltage on 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 AC voltage on one of the primary windings of the transformer. How to do this, you can see in the photo below.

The device should show about 150 volts, and the voltage should, as it were, "float", that is, change. If this does not happen, then the microcircuit is most likely out of order. You can replace the chip 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 "measuring constant voltage" mode and connect the negative (black) probe to the second slot on the connector. This is a common (negative) contact. With the second 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. Pay attention to the larger diode. It is labeled SR-360 and the like. It crashes most of the time. By replacing it, you can also solve the problem when the satellite TV receiver does not turn on. Again we measure the voltage at the terminals.

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

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

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Written by Administrator on December 07, 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 it is 12 months) ended, and the receiver suddenly failed. A new one is expensive, and in most cases, repairs will not be difficult and will cost a penny, if you are at least a little friends with a soldering iron, the main and most common malfunctions can be easily fixed by yourself. Consider such a repair using the example of another receiver from Tricolor TV GS-8300 N.I must say that the device is not of the best quality, and the money that Tricolor TV 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 properly.

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

An 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 the initial level of a radio amateur. Usually failed capacitors have a yellowish appearance, or a small brown speck on the circuit 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 rally. The firmware often flies, the evidence of this is usually the complete freezing of the receiver. In this case, "flashing" will help. I also want to say about another reason for the malfunction, which may arise due to poor-quality installation. Water in cable. If the outer insulation of the cable is broken, then water from precipitation can get inside and easily enters the receiver through a hose, sometimes flooding all its insides. The condition of the cable must be monitored throughout the life of the device.

Read also: U660e DIY repair

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 appeared for the public. These are satellite receivers, conditional access modules, antennas, converters, etc. Whether we like it or not, sooner or later breakdowns happen to them, which cause us to feel the loss of our favorite thing.

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

Equipment breakdowns occur for various reasons - voltage drops, failure of various components, wear and tear of the equipment itself from its venerable age, one can also note the incompetence of the owners themselves, for example, incorrect replacement of software in satellite and cable receivers.

The failure of the power supply is perhaps the most common type of malfunction of digital terminals. It arises for various reasons: poor-quality power supply (see photo), poor-quality radio components are used, especially this is de facto in Chinese technology.

Also here can be attributed a violation of operation, dust, dirt, as a result of which the thermal regime is not correct (see photo).

The service center is a structural unit within the company. He is entrusted not only with the repair and maintenance of products sold by our company, but also with the repair (including warranty) of satellite equipment of other companies. Our customers 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. A flexible policy towards corporate customers allows us to provide proper service and satisfy the interests of all customer groups. This is more than 1000 pieces of equipment per month. Of course, the professionalism of the employees, the equipment of the service center with professional equipment, tools and technical documentation make it possible to carry out such large volumes. Therefore, our service center performs repairs of high complexity: for example, the replacement of processors in BGA packages. The repair takes place as soon as possible.

The supply department, in addition to its main function - the purchase of equipment, also deals with the needs of the service center, purchasing components necessary for repairs. And here it is worth noting that the selection and purchase of components for repairs takes place according to the following criterion: the quality of the parts is in the first place, their price is in the second place, 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. The work performed is guaranteed.

Of course, unforeseen moments happen - for some reason, repairs are 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, the following were found out of order:
– mains capacity C5 – 47µFx400V
– Q1 – CS2N60F
– R8, R11, R13 – 3 ohm each (size 1206)
– R9 – 47 Ohm (1206)
- U1 - it was not possible to determine its type by the marking on the case.

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

Instead of the burned out Q1, SSS4N60B was installed (TO-220F case)

On Telesputnik they posted a power supply diagram.

There are inaccuracies:
1. The lower terminal of the primary winding must be connected
to the connection point of anode D6 and drain Q1
2. Position designation C2 and C3 is incorrect. C3 must be connected to the 3rd pin
U1, C2 to the 4th pin of U1.
3. Rating C3=68nF
4. There are two capacitors C1 in the diagram
5. Missing C12
6. Primary land is labeled in the same way as secondary land.
7. Missing C8
8. Q2 - MOSFET NTD14N03R
9. Rating C11=2200pF
10. Type D8=SR560
11. The positional designation of U3 and U4 is incorrect - they must be swapped.
12. Rating C5=47µF

The receiver turns on, there are 18 volts on the LNB. There is no video signal, it gets very hot (does not hold a finger) stv 6419 .. because of it there may not be a video? no other point? (in the sense there is no more video signal from where?) the receiver switches channels ..

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

the video signal from the STi5119ALC processor comes in, you can check it with an oscilloscope at a test 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 chip, there is no output to R91 from it, the culprit is no 12 volts on the board, respectively, there is no power supply + 12V on the 3rd leg of STV6419, a 12 volt D3 zener diode is faulty near the power connector

There was such an answer: if you use only a composite video signal, most likely you can simply throw it away (replace it with a jumper). Where to put the jumper? if this is the right advice..

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

Zener brand and parameters:

Power + 12V to the 3rd leg STV6419.
In a chain: XP5 connector 9th leg -> R81 (300 Om) + VD3 zener diode (12V) = stabilizer + 12V -> L3 -> 3rd leg STV6419.

Zener diode analogue:

VD3 STV6419 did not find a similar zener diode (SMD). I 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 a thunderstorm, 6419 swelled. After the replacement, the image did not appear, but when checking the strapping, two resistors were broken, R91, R95. Replaced it and everything worked.

One more problem:

And yet, instead of 13, 18 Volts, 24V went to the LNB. Needed a replacement DA1 (LM317T). And that's it, the flight is normal

The same situation with the GS-8304 receiver:

After 5 years of work, the GS-8304 suddenly stopped broadcasting, although the indication is working properly.
The zener diode has broken into a short circuit. Zener brand MMZE5242B.

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

Repair of satellite receivers produces much more often than converters. This is due to the low quality of receivers made in China.
The main causes of receiver failure are the drying of electrolytic capacitors, converter failure, damage and ingress of precipitation into the antenna-feeder system (cable), damage to the receiver’s software firmware and failure of the receiver’s power supply as a result of a power surge, etc.
What are the nuances of repairing satellite receivers? If the receiver works, but is "buggy", then you first 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 the converter to check if it is known to be good.

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 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 rapid 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 an image does not appear on your TV screen, then go to the main element of the satellite dish - the receiver.

Very often, the cause of a malfunction of a satellite receiver is a "rally" of the firmware. In this case, only its flashing will help. Here you will need a null modem cable, a bootloader, software, and experience with receiver firmware.If you do not have such experience, then entrust this matter 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 malfunction of the power supply.
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 let's 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 power surges. If, after installing serviceable parts, the power supply did not begin to 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 a high frequency current and supplies it to the transformer. The winding of a transformer has several parts. One part is used for control. The PWM controller measures the voltage on it and changes the duty cycle and the frequency of the pulses supplied to the primary winding of the transformer. This ensures that the output voltage is stable.

In a switching power supply, control is also carried out for the supply voltage of the digital circuit of the receiver (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 needed to bias the varicaps of the high-frequency tuner.
A voltage of 12 volts is supplied to power the analog part of the receiver circuit (sound and video).
A voltage of 5 and 3.3 volts is necessary to power the receiver's digital microcircuits.

Troubleshooting should begin with 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 circuits and the condition of the capacitors. If they have ruptures and swelling, then they must be replaced immediately. Electrolytic capacitors dry out quickly and lose their rated capacitance. And this leads to the inoperability of the electrical circuit as a whole.
Check voltage regulators and Schottky diodes.
When testing diodes with a digital multimeter, they may be good, but have leakage current. This is unacceptable and often leads to malfunctions. Keep this in mind.

Video (click to play).

If the troubleshooting was unsuccessful, then you should pay attention to the PWM controller and its piping circuit. Its replacement (chips) often brings the receiver back to life. Check the winding of the transformer and chokes for an open circuit.
Another cause of the malfunction may lie in the non-soldering of the 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 one more thing I would like to say. Do not buy suspiciously cheap satellite receivers. You can run into a fake that will not work for a month. Good luck with your repair and bye!

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Do-it-yourself 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. Here is the picture before us:

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

Now we need to unsolder it and check the rest of the radio elements. I’ll explain the check in a simple way: you need to check all transistors and diodes (zener diodes) for a “short circuit”.

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

We measure the voltage at the output of the power supply and, if they match the values on the board, you can connect the cable.

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 complicated 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, one cannot do without doing anything, it is impossible to learn anything.

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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. Here is the picture before us:

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

Now we need to unsolder it and check the rest of the radio elements. I’ll explain the check in a simple way: you need to check all transistors and diodes (zener diodes) for a “short circuit”.

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

We measure the voltage at the output of the power supply and, if they match the values ​​on the board, you can connect the cable.

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 complicated 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, one cannot do without doing anything, it is impossible to learn anything.

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We measure the voltage at the output of the power supply and, if they match the values on the board, you can connect the cable.