Always try the old unplug all connections, remove power for a few minute routine too.
After that, it needs repair.
After power on led tv shows smart tv screen then goes blank and becomes unresponsive. It won't turn off and must unplug to power off.
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After power on led tv shows smart tv screen then goes blank and becomes unresponsive. It won't turn off and must unplug to power off.
I'm very sorry for any inconvenience this may have caused you. Unfortunately, this sounds like it may need servicing. Here’s the thread where you can get details on setting that up: http://forums.cnet.com/7723-13973_102-542437/service-issues-click-here-for-help/
Regards,
HD Tech