If the standby indicator of the TV keeps blinking, please follow the below methods to do the troubleshooting:
1.If the TV could start up successfully, make sure the LED indicator stays on Normal: TV Settings - System - Advanced Settings - LED Indicator
2. If the TV cannot start up successfully, make sure the TV remote and the physical power button on the back of the TV works properly.
3. Try to power cycle the TV. You could unplug the power cord from the socket and plug it back in.
If the issue cannot be resolved, please feel free to call the TCL hotline for further help.