That would be a TV tech or engineer on their bench with the service manual, test gear and most likely spare parts. No TV tech or engineer would work such any other way. There are folk new to repair that think you can correctly guess what board or part without the service manual and prior work in the field.
The more repairs you do, especially on the model line in question the better you get as you learn how the TVs work and common things that go wrong.
Your best first move is getting the service manual to see what it says to do first.
IM PRETTY SURE IT IS ON ONE OF THE MAIN BOARDS INSIDE THE UNIT. ANYONE KNOW HOW TO DETERMINE EXACTLY WHAT THE ISSUE IS AND WHAT PART I NEED, OR ANY RESOURCES TO USE TO GET IT FIXED