Tv display and audio not working still after I tried methods online

I'm turning my TV off and it makes this hissing rattle noise, but when on it's display is just a black screen, no logo, nothing. No audio comes through and I've tried everything I'd been able to find.

I did the home button cheat code, unplugged it for a few minutes before plugging it back in, and finally held the manual power button below the TV for as long as it took to register the shut down, before turning it back on the same way.