The most common cause of power supply failure in a TV is environmental issues. These issues can include moisture ingression, surges and transients, induced power-line surges and transients, lightning strikes, and reactive loads.
Moisture ingression is a common problem in TVs, especially if they are not properly sealed or if they are exposed to high humidity environments. Moisture can cause corrosion and short circuits within the power supply, leading to failure.
Surges and transients are sudden increases in voltage or current that can occur in the power supply. These can be caused by lightning strikes, power grid fluctuations, or the operation of other electrical devices in the vicinity. Surges and transients can cause damage to the components within the power supply, leading to failure.
Induced power-line surges and transients occur when electrical devices connected to the same power grid generate spikes in voltage or current. These induced surges can be caused by devices such as refrigerators, air conditioners, or large motors. The power supply in a TV may not be designed to handle these sudden increases in voltage or current, leading to failure.
Lightning strikes can cause a power surge that can travel through the power lines and damage the power supply of a TV. Even if the TV is not directly struck by lightning, the electrical surge can still cause damage to the sensitive components within the power supply.
Reactive loads, such as regenerative motor drives, battery charging systems, or super-capacitors, can also cause power supply failure. These devices can generate spikes in voltage or current when they are operating, which can overload the power supply and cause it to fail.
In my personal experience, I have seen several cases where TVs have failed due to power supply issues. In one instance, a lightning strike nearby caused a power surge that damaged the power supply of a TV. The TV was no longer able to turn on and had to be repaired.
In another instance, a TV in a high humidity environment started experiencing intermittent power supply failures. Upon inspection, it was found that moisture had seeped into the power supply and caused corrosion, leading to failure. The power supply had to be replaced to restore functionality to the TV.
To summarize, the most common cause of power supply failure in a TV is environmental issues. Moisture ingression, surges and transients, induced power-line surges and transients, lightning strikes, and reactive loads can all contribute to power supply failure. It is important to protect TVs from these environmental factors to ensure their longevity and proper functioning.