1. A wrong setting. In some models previously produced the TVs menu is a function "Auto off". Prolonged absence of the reception signal , the TV turns off. Please note that activated the function or not.Disable auto power off, and everything will be fine.2. Fault. If the TV is new and in warranty, in this case, you must contact the authorized service center for repair. In the case of the expiration of the warranty period, you can go to any workshop on repair of household appliances, preferably with qualified personnel. Here you are entitled to receive post-repair warranty within a certain time. Is of great importance that the conditions in which works the TV. High temperature, humidity, dust, aggressive environment disrupt the normal operation of the circuit components, the oxidation and destruction of the contacts, overheating that eventually leads to spontaneous disabling. Sometimes it is enough to blow a strong air flow chassis TVand replace the fuses, clean the oxidized contacts. Also may be the result of the race and the voltage drop in the network.If you have basic knowledge in electronics and know how to use a soldering iron and a tester, then you can try to find the reason off the TVand fix it. First, check visually the condition of the capacitors of the power supply. Electrolytes may eventually lose efficiency, to dry, to swell, from under the hood appears to flow of the electrolyte, it can be seen on the wet spots around them. Sometimes it leads to corrosion of the copper tracks, and on both sides of the PCB. In some cases, it is sufficient to replace the faulty capacitor. Try to conduct a complete visual inspection and installation of panels. To do this, arm yourself with a powerful magnifying glass and provide good lighting. With time of operation due to the heat appear annular cracks in the tracks of printed circuit boards, revealed poor soldering of the circuit elements. All suspected sites should be carefully soldered, which often resolve the problem it shut down. Also a possible malfunction in the system horizontal or vertical sweep fail trasformatori or elements in their circuits. Such damage is already more difficult to identify the non-specialist. You can ask for help via the Internet. There are many sites and forums where I will share with you comprehensive information and tips specialists in repair of television equipment. Note that repair of TVand belongs to the category of particularly hazardous work as there is a high voltage of several thousand volts, and without proper knowledge and skills, you are putting your life in serious danger. Soberly assess their capabilities, if in doubt, trust the experts-telemaster.