LED Backlight or main board?

I have a Samsung UN35M5300AFXC 32 LED tv. I have the issues of a blank screen... however, when I plug the system in I will often get a 'splash screen' for about 1 second. Tore the set down to the LED strips being viewable, plugged it in....both LED strips light up for about 1 second...then nothing. I tried replacing the T-conn board with a replacement board with no luck. I am thinking the LED strip aren't the problem, but it looks like the main board is bad with regards to driving the LED strips?? Everything else seems to work as it will turn on to some internet channel (or something) that I can change channels with the remote and hear audio. If I shine a bright light on the screen I can see the screen menu and move around with the remote....Granted I should probably just trash the whole thing....but it has now gotten personal where I refuse to let this TV beat me...lol. So what is the general consensus...replace the main board...take it out back for target practice...or is there something else I am missing...?

Thanks for the response

Not sure what you mean by…”Disconnect the power board to the main board ..."The only boards on this unit are the main board (Power cord plugs in to a socket on the board) and the T-conn board.

Don’t know if you can see that clear enough. Where should I check the voltages and what voltage should I be looking for? Thanks for the response