My 65” tcl Roku just went black

So, my 65” tcl Roku just went black. It has sound but the display not showing. Had it 25 months. When using the flash light I can see the display faintly. So is this a backlight inverter/ led problem,or something else? Haven’t had a chance to see look at the model number yet but where can I get the replacement parts from. Of course it’s sad but I Love working on stuff like this in my spare time. Any help will do. Tried the resetting mode thing and replaced both the hdmi and power cord already and it didn’t help. Tv will flash good picture for a fraction of a second then go back black. Thanks