If the AV output does not work.

Repair of the receiver Tricolor GS8300

Hello. Today I'm going to show you a solution to a common problem. One fine morning, going to watch TV, I was upset by a black screen. Looking at the tricolor receiver, he noticed that he seemed to be dead. 🙂

The GS8300N did not respond to the power supply (the indicators did not light up). Since the warranty ended a long time ago, I began to disassemble this device. The picture was unpleasant, the power supply of the receiver burned out. This receiver, like the TV from the day of purchase, was powered through a voltage stabilizer, however, this did not save him.

The power supply capacitor dried up and swelled, several radio elements burned out from overheating.

In order not to breed plagiarism with the text, I will post a video that helped me quickly repair the receiver's power supply. It details the repair process. In addition, the circuit has been slightly modified and works perfectly.

I will show the cost of repairs, and then decide for yourself whether it is worth it or not.

Microcircuit - 60 rubles
Diode - 2 rubles.

If the arms are straight, then it's worth it!

After checking the diodes, I found one punched.

Here is the original power supply circuit of the receiver.

And here it is, the video! 🙂

If it was useful, I'm always happy for thanks. If something is not clear, I will definitely answer in the comments. I got it right the first time and this redone scheme works great.

Be sure to take a look here:

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SUPRA STV-LC42T400FL (V1N06)
Main HK.-T.SP9202P53

Backlight Driver OB3350CP
Fault:
The backlight turns off in the TV, the sound and image remain, you can see it on the MENU matrix.
Turning off the backlight occurs arbitrarily, the backlight can go out right away or it can work for half an hour. (according to the client)
In a workshop:
When it arrived for repair, the TV worked for 5 minutes and the backlight turned off.
The solution to the problem did not come immediately.
The first thing I thought was LEDs!
Opened the lid, checked the voltage on the OB3350CP

All voltage is normal when the backlight is working!
When the backlight turns off, the voltage on leg 2 is 0 volts
I decided to open the panel to look at the LEDs ...
Checking the result with the device did not reveal the exact result, it seems that all the LEDs are normal in terms of current, there is no big discrepancy, all the bars glow perfectly.
The only thing that alerted and caught my eye was the place around the diodes, obviously burnt, on some strips it is more noticeable, on others less.
In general, again I installed all the strips on the panel and turned it on without a matrix! UPss... The LEDs blinked and did not light up.
But before I dismantled the panel, the backlight worked for two or three minutes and turned off.
Checked EVERYTHING again! No problems, everything is fine. I decided to check each LED separately for current consumption, I did not find any critical differences.
Well maybe? The TV worked, personally accepted it for repair, and together with the client saw the perfect image.
And now all the LEDs flash and immediately go out, the LED on the TV panel is green, that is, the TV remains in operation, you can turn it off with the remote control and turn it on again, then the backlight will turn on again and turn off abruptly, time no more than 2 seconds.
I checked the voltage on the OB3350CP driver again, everything is normal, except for the voltage on the 2nd leg, it appears there for a second and immediately disappears.
I decided that the problem is in the chip itself or in the LEDs. There was no such driver available, I decided to change the LEDs for new ones, since I bought it recently.
Further, the replacement of the LEDs did not give a result, everything is the same, the backlight blinks and immediately goes out.
I bought two OB3350CPs, changed all two in turn, but the result is the same.
I decided that the problem was with the lane, but to clear my conscience I decided to check the entire OB3350CP harness again. I cleaned the glue on the backlight connectors, there are also resistors there, washed everything with alcohol and let everything go around under the microscope .... all the rules!

Only one resistor raised doubts, according to the marking it is 01C (10 kΩ), but when checking for Ohms, it behaves strangely, it increases, then decreases to the norm of 10 kΩ.
Once again I washed everything and soldered this resistor and Finally, it went into MΩ.

All repairs are completed, the TV is assembled and put on the run!
I highlighted the problematic resistor in the photo, there was no circuit during the repair, so it seemed to ring on the third leg of the OB3350CP.

In general, nothing new, who does not work and does not make mistakes)) Just a repair ..., I think in this chassis it will be another type due to the quality of resistors marked 01C.

Repair GS-8300

In this article, we will repair the "tricolor" receiver with our own hands. Often there is such a problem that the warranty period has ended, and the receiver has suddenly broken down. Buying a new receiver is expensive, taking it to a service center means depriving yourself of watching satellite TV for a long time. But in many cases, the breakdown of the device can be corrected independently, without spending much effort and large sums of money. If you know how to solder, then it is easier to figure out the malfunctions yourself and fix them.

As an example, we will use the GS-8300 N Tricolor TV receiver. It is worth noting that the quality of the receiver leaves much to be desired, since it costs decently. However, many subscribers use this particular receiver, and not all of them work properly.

we will use the receiver for television "Tricolor TV" GS-8300

The main and most common problem of most receivers is a malfunction in the power supply system and voltage conversion. In addition, a short circuit in the coaxial cable from the LNB often causes damage to the modulator. Only in the latest models did they begin to use good protection, which, when closed, stops the supply of voltage to the converter until this short circuit is eliminated.

So, a problem arose: the receiver does not turn on and does not show any signs of life at all, and the indicators on the front panel do not light up. We tried to distort the plug from the outlet, turn on / off the toggle switch - it does not help.

Then we understand further. First, be sure to unplug the plug from the outlet and remove the top cover with a screwdriver. We need to look at the electronics of the device. It is important to remember here that when removing the cover, we will definitely break the warranty seal.

Therefore, if the warranty period has not yet expired, it is better not to go in yourself, otherwise you will not be able to repair your receiver under warranty later.

And if the guarantee has passed and you have no one to rely on, then go ahead - break the seal.

"Tricolor TV" GS-8300

Removing the cover reveals printed circuit boards with various components. They are interconnected by wires. The photo shows some devices with a description. We need to find the power board. It has a transformer and a supply for the power cord, so it is not difficult to find it. The first thing you should pay attention to is the fuse, which is usually installed at the beginning of the circuit. The fuse can take many forms, such as a glass capsule with a conductor, or a small plastic box in which the fuse is placed. In the second case, you must first remove the cover of the box (you can use tweezers or tweezers) to get to the fuse itself. Next, you need to check the fuse with a tester or multimeter for a break. If it's blown, which often happens, then go to a radio store, buy the same fuse and just change it. If everything is fine with the fuse, then we check further down the chain.

Another element that often breaks is the transformer itself. Such a fault is detected by measuring the voltage on the secondary winding. It is worth noting that the replacement of the transformer is not for everyone. If you are not sure that you can change it yourself, then it is better to take your receiver to a repairer, and if this does not seem difficult for you, then go for it.

Receiver internals

Another malfunction is the failure of the electrolytic or oxide capacitor at the input due to drying out. To detect this breakdown, you need at least a little understanding of radio mechanics. A faulty capacitor is usually yellowish in color, and a small brown spot may be observed on the board at the base of its legs. In addition, you can compare the nominal and measured capacitance of the capacitor to determine its health.

The diode bridge in the receiver converts the alternating mains current into a direct one.

The diode bridge can also break. This is easy to check, since a semiconductor diode has one main function: to pass current in one direction, but not in the other.

In the case we are considering, a breakdown occurred with the transistor of the primary winding of the transformer. It has a heatsink to dissipate heat, so it's pretty easy to find. The fault was detected as follows: they measured the voltage at the emitter of the transistor, it was not there, the primary winding was not powered, which means that all other parts are de-energized. The cost of the transistor is about 30 rubles. To replace it, we need a soldering iron. We fix the problem, and - “Hurrah! Earned! - Receiver is back to normal. Note that the transistor does not break often, mostly the receivers fail due to the fuse.

Consider another very common malfunction - firmware rally. This happens quite often. A sign of a firmware rally is the complete freezing of the receiver. Then we just need to reflash the receiver.

The reason for the failure of the receiver can also be poor-quality, unprofessional installation. If the external insulation of the cable is broken, then rainwater or snow can easily penetrate the inside of the cable and, like a hose, seep into the receiver, flooding all its internal contents. Therefore, you need to monitor the cable, if there are any kinks or insulation violations.

Those who do not understand anything about the internal structure of satellite receivers, or who have no time to deal with this at all, should not despair if the device breaks down. Service centers have not yet been canceled. There you can contact with your problem and experts will help you solve it.

Receivers fail for various reasons.

Receivers fail for various reasons - this is a voltage drop, and the wear of the device itself due to heavy use, and the failure of certain elements. This can also include breakdowns due to owners who themselves decided to sort out the problem without having special skills, for example, they incorrectly replaced the firmware in a satellite or cable receiver.

The power supply is perhaps the most broken part of the receiver. The power supply can break due to a poor-quality power supply, due to poor-quality radio components (especially on cheap Chinese equipment).

Dust and dirt can also cause the receiving device to break down, creating incorrect thermal conditions.

Dust and dirt in the receiver can also damage the receiver.

The service center provides repair and maintenance of various satellite equipment. Moreover, repairs are carried out by specialists and on professional equipment. Almost any defective part can be replaced with a new one. The timing of the repair will depend on the availability of parts in the service center. If any part is missing, it will be ordered from suppliers, which will take some time. But in large, serious centers, as a rule, parts are always available.

Consider another situation: the receiver failed after a power surge. After opening the lid, it was found that the following parts had burned out:

network capacity C5 - 47µFx400V

R8, R11, R13 - 3 ohms each (size 1206)

R9 - 47 Ohm (1206)

U1 - type not defined

On the Internet, we found a page with a table for identification and selection of analogues (for example, http://remont-aud.net/ic_power/), we look at it, what we have, what we don’t have. We will replace the last part with SG6848 to minimize interference with the factory circuit.

We carry out the dismantling of defective parts (circled in red in the photo):

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)

Installing new children

instead of U1 - SG6848

instead of R8, R11, R13 - one resistor 1.8 Om x 0.5W

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 of 3V3 at the cathode VD8, we will stop at a nominal value of 11 kOm, U=3.36V (at 10 kOm U=3.28V, at 12 kOm U=3.41V)

instead of the burnt Q1 - SSS4N60B (TO-220F case).

Installing new parts in the receiver

GS-8300 PSU Schematic

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 the Tricolor TV company 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.

Power circuit failure:

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 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.

Opening the cover, we see printed circuit boards with many components interconnected by wire buses. Below are photos describing some of the devices on the board. First of all, we are interested in the power board, it is not difficult to distinguish it by the transformer installed on it, and the supply of the network wire. And the first thing we pay attention to is the fuse. It is usually installed at the beginning of the chain. The fuse will not necessarily have the shape you are used to (a glass capsule with a thin conductor inside), for example, in my case, the fuse is enclosed in a small plastic box, and in order to get directly to the fuse itself, the cover of this box must be removed. This is done very simply, for example with tweezers. Having reached the fuse, we check it with a tester or multimeter for a gap. If the fuse is blown, which by the way happens very often, we go to the radio store, buy the same one, change it and that's it. If this is not the case, we check the details further down the chain. Often the transformer itself fails, we can detect such a malfunction by measuring the voltage on the secondary winding. I must say, not everyone can possibly replace the transformer, if so, then it’s better to take the receiver to the workshop, but if you are confident in your abilities, then go ahead, for example, it won’t be difficult for me.

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 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.

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 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 atmospheric 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.

Electronic devices surround us everywhere: on the street, at work, at home. With the rapid growth and availability of satellite television to the masses, 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 occurs for various reasons: a poor-quality power supply (see photo), poor-quality radio components are used, especially this is de facto in Chinese technology.

This also includes 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 division 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.

The receiver died after a power surge in the network.

At autopsy, the following were found out of order:
- network 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 marking on the case.

According to the table for identification and selection of analogues, the last part was replaced by SG6848 with minimal interference in 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 of 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)

PSU diagram GS-8300

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

If the AV output does not work

Question:

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.

Decision:

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

Zener diode analogue:

VD3 STV6419 similar zener diode (SMD) was not found. Put 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 turned out to be open, 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...