If you leave the TV with the power cord (mains lead) disconnected, the electricity that remains in the unit will be discharged. If the situation does not change after pressing the POWER button on the remote control, try the following steps. If you unplug and plug in power cable, it may have same effect as the reset steps above.
Wait for approximately one minute, and the TV will turn back on. If it does not reboot, press the POWER button on the remote control to turn on the TV. In that case, you can also select Restart to restart. NOTE: Depending on the model and OS, the Cancel or Restart screen may appear after pressing the POWER button on the remote control for 3 seconds or longer. Point the remote control to the illumination LED or status LED and press and hold the POWER button of the remote control for about 5 seconds, or until a message Power off appears.If TV is turned off, turn it on first and perform the following operation.When an external USB hard disc is connected to the TV, disconnect the USB cable from the TV before resetting.
Perform the following operation to reset the TV. As with these devices, resetting your Android TV is an effective method to resolve some issues such as "the picture does not appear", "only sound is output", "the remote control does not work", or "the App is extremely slow." Your BRAVIA TV runs the Android™ OS, which is also used in many smartphones and tablets.
For details about how to reset a BRAVIA TV other than an Android TV, refer to the article How to perform a power reset on a Sony television. IMPORTANT: This solution is applied for Android TVs.