Samsung LE40D550 LED TV: No Picture (Black Screen) with Sound - Repair Assistance

Hello.
I got a Samsung LE40D550 from a friend. The problem is that there is no picture. My friend claims that his TV was playing suddenly, the picture turned black, the sound is. Please help in repair.
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I would start by checking the backlighting. If you shine a flashlight at an angle close to the matrix, is the content of the image visible?

Matrix highlighting works, I checked it before writing this post

What else did you check before writing this post? At least some voltages from the power supply, or even the power supply of the T-CON?

I did not check anything else because I do not know myself. I took the back cover and you can see that the matrix is illuminated because through the small holes you can see the light.

The matrix backlight can be seen very well without removing the housing ...

It is better to buy a second TV, it will be cheaper. Or have the TV serviced. Repairing the LCD TV is not to connect the flashing diode. Here you must have some idea about the measurements, the principle of operation of individual blocks, etc.
Can you measure the voltage of the power supply? Do you know what it is and where is it located?
Beware of the voltage dangerous to health and life !!!

I have a university degree in electrical engineering. The voltage can only measure where and in which place.

A service shop or at least a diagram has already been found by a colleague? Where to measure the power supply voltage? At the outputs of the PSU ...

I did not find service providers, but a colleague above wrote to me to check the voltages and compare them with the voltages given on the power supply board

Hello!! In most cases, if the backlight works and there is a voice but there is no picture, it may be symptoms of cold solders in the main power supply. You have to unscrew the power supply board and turn it around to see the paths next to the double diodes (in the shape of a transistor), transistors and diodes. Look at overheated places.

I will step on the topic because I do not want to start a new one, so as not to clutter. I have a Digihome 42278FHDDLED TV. Inside components used in other popular TV sets: 17MB82S motherboard and Vestel 17IPS71 power supply.
After pressing the power button, only the matrix illumination turns on. I replaced the motherboard with a second one - it did not help. I replaced the power supply with a new one - it did not help. There is only one part left to replace, namely the TCON. However, I have never read anywhere that TCON can cause a complete lack of a picture, only distortions, and I am in a bind whether to buy a new TCON or it can be something else. Thanks in advance for your help.

Below is a picture of all the elements of this TV.

dd74 wrote:

However, I have never read anywhere that TCON can cause a complete lack of an image

And why should it not be able to cause when it is a matrix control module?
By the way - there may be something else.

Artur k. wrote:

dd74 wrote:

However, I have never read anywhere that TCON can cause a complete lack of an image

And why should it not be able to cause when it is a matrix control module?
By the way - there may be something else.

About you see it I didn't know it could cause a complete lack of a picture. And could you write what else could be damaged, please. Just in case it turns out not to be TCON. Thanks

I have a similar problem with the SAMSUNG LE32B550 TV. There is no picture, there is sound. The matrix displays the image but there is no backlight. The backlight briefly flashes when switched on and goes out steadily.
Does it make sense to play with it? I would not like to buy a new TV because I am renting this flat, but I have to react somehow.

It makes sense to play with it. A decent service will repair such a defect without major problems, and the repair cost will be incomparably lower than buying a new TV.

For information - the QGAH02094 inverter was killed
I replaced the entire power supply assembly.

Hello

The same situation with the five-year-old Samsung UE32EH5300 TV. When I turned on the tv black screen, I could hear a sound. After shining a flashlight, you can see that the matrix is illuminated. Replacing the power supply with a used one for PLN 129 with alledrogo. The TV flashes. Thanks.