My QLED TV wont switch on properly. When i press the power button on my remote, the TV comes on with no picture and muted sound. To get it to come on "properly", i have to keep my finger on the power button continuously until "QLED" appears on the screen then immediately take my finger off the power button. That said, for the next 20 minutes or so, the TV flickers constantly and switches itself off and on, randomly, about half a dozen times. Can anyone please help with this issue?