Fix Dark-Screen TV

My television suddenly shows a completely black picture, yet the audio still plays. I power-cycled the set but it made no difference, and I’m not sure where to find – let alone tweak – any brightness or back-light controls on the remote.

What I need from you is clear, step-by-step guidance to isolate the fault and get the image back. Please assume I have basic household tools and can follow instructions, but no service-manual knowledge. Remote assistance via chat or call is fine; just walk me through everything from checking cables and inputs to navigating the on-screen service menu or diagnosing a failed back-light/T-con if it comes to that.

Your deliverable is simple: a set of instructions that actually brings the picture back, or definitively tells me the component that has failed so I know what part to replace or whether I should call in a hardware repair.