Have been having numerous random issues with TV, no sound, switches itself on/off etc.,contacted Sony Support for advice and they recommended the following troubleshooting guide.
The TV has now been functioning OK for the last week.
Reply from Sony: In attempt to resolve the issue, please find the troubleshooting steps below:
1-Disconnect any external devices connected to the back of the TV.
2-Unplug the main power cord of the TV, and plug it back after 2 minutes.
3-Update the software version by following the below steps:
( Help - System Software Update).. The latest software version should be: (v6.5042).
If your TV does not detect the latest software version, please update it manually following the link below:
https://www.sony.co.uk/electronics/support/oled-tvs-android-a9g_ag9-series/kd-55ag9/software/0025872...
4-Clear Cached Data & Reboot the television:
Press on: (home - Settings - Device preferences - Storage - Internal Storage - Cached Data - Select Yes to clear it).
5-Press on the green power button for more than 5 seconds until a message appears on the screen " Powering Off " or " Shutting Down".
6-Connect your TV to hot-spot following the below: (Home - settings - network - network setup - easy - wifi - connect by scan list - then choose the name of your smart-phone and enter the password).
