When gear lands on my bench, I don't start with a screwdriver. I start with questions — and I would rather ask them before the case comes off.
What exactly does it do, and when? Dead always, dead sometimes, or dead only after it warms up? Intermittent faults tell you more than total ones, but only if you catch them in the act.
What changed? New outlet, new house, new cable, new pet? Gear that worked for ten years and died the week you moved is telling you something about the move.
Has anyone been inside already? Previous repair attempts are the most common complication I see. Nothing wrong with DIY — I just want to know which screws I am loosening and what an earlier set of hands may have changed.
Are these the original symptoms or the current ones? A unit that was "fixed" and now does something different is a different problem wearing the same cover.
None of this is ceremony. Each answer either points somewhere or crosses something off, and crossing things off is most of what diagnosis is.
So before you post a repair question here, answer those four in your first post. You will get better answers faster. What is the strangest answer you have ever gotten to "what changed?"