If you connect using a “tulip-to-tulip” cable, which is included with most tuners, then you may have connected the set-top box to the TV incorrectly. They have two rows of contacts. The output diode and capacitor are located after the pulse transformer. I downloaded the archive with the firmware from here, the appearance of the board and its number match. Digital DVB-T2 set-top boxes. The most common malfunction.
You may have a virus that intercepts links.
When you reduce the color removal, the blurriness remains.
This appears to be testing the power supply to the active antenna. Since the author has never come across “cold” DVB-T2 set-top boxes; they all get very hot during operation, after the end of the warranty period, it is advisable to measure and record the input and output voltage values of the stabilizers installed on the board, and also photograph the circuit board on both sides so that all the inscriptions were visible, this may be useful when repairing a failed device.
Problems with the demodulator, of course, can also affect the inability to receive: either the quartz is faulty, or the demodulator itself is faulty, for example, non-contact.
May God grant you good health for many years to come.
Repair REXANT 35 DVB T2
DVB-T2 tuner Globo GL50 - repair, device, diagnostics
Cyclic reboot, freezes during loading, etc. On one 1.
The capacitor plates may short-circuit with each other or become detached from the terminals.
The design of a digital TV intended to operate on a DVB-T broadcast network must provide the ability to reproduce high-quality television images when using various additional video data sources, for example, a DVD player.
Regarding your question: 1. As you obviously guessed, the repair consists of sequentially replacing all electrolytic capacitors installed on the board. Then we replace the quartz resonator in the tuner if it is present in the tuner unit. Try changing the connection to the TV - instead of the “tulips”, install an HDMI cable, or vice versa.
Perhaps there are other electrical appliances in the apartment that have suitable batteries or accumulators installed. Well, let's start with the easy option - an indoor antenna is connected, but not an outdoor antenna after a thunderstorm. Comparing two identical receivers, I realized where the voltage should be.
Technical characteristics of the headend
How I repaired a DVB-T2 digital television set-top box. The output voltage is set by resistors 1R1, 1R2. When you turn it on, the “no signal” sign is lit; when you connect the antenna, the sign disappears for a second or two and appears again, as if it’s trying to catch a signal. If normal, look for monitor on the website. Much more often, DC-DC converters burn out in receivers.
If voltage appears, one of the secondary converters is definitely faulty. The viewer can select the desired program by issuing the appropriate command from the remote control, the signal from which is processed by a microprocessor. Perhaps the tuner chip has died. At a voltage of 1.2 V, the processor worked without errors in all operating modes of the set-top box, consuming a current of about 0.6 A. To speed up page loading, some of the comments have been moved to the continuation of the article.
If they do not comply with the standard, we repair the power supply, otherwise we unsolder the flash memory chip and insert the firmware into it through the programmer. Check all supply voltages 3.3 1.8 and 1.2 V. Repair of TV set-top box DVBT2 MYSTERY MMP 75DT2
A short introduction to the power supply circuit of the set-top box
Just a little background for those who are not in the know so that you can figure it out. Pay attention to the photo. Click to enlarge.
Power supply from mounting side
Power supply solder side
In short, the power supply consists of:
- The primary “Hot” part - It is called Hot because it is dangerous, connected to the mains voltage of 220 volts. Please note that even after unplugging from the socket, there is still a charge there for some time that can cause damage..
