Power supply failures often cause televisions to shut off by themselves. The problems may be in the television's power system or from the source of power. Problems with cable boxes can make it look like the television is turning off on its own.
When determining why a television is turning off on its own, it is important for owners to ensure that the problem is with the television and not with a cable box or another connected device. Most televisions have a light on them that turns off when the television turns off, and if it remains on while the screen goes black, the problem is probably with the connected component.
Televisions draw a considerable amount of power, and any interruption can cause the television to turn off on its own. Homes that supply inconsistent electricity can sometimes cause a television to go off on its own, but there are normally other clear signals that the home's electrical system is faulty. The problem can also lie in the television's wiring or power supply.
All televisions have a power supply that controls the electricity drawn from various components, and this power supply can go bad over time. They can fail suddenly, but they often break down slowly over time. If the television begins to shut down more frequently, the power supply might need to be replaced.