Signal flow first
Most faults show up far from where they begin. A drifting lip-sync problem may start at a clock reference, and a flat picture may start with lighting levels rather than the camera. We trace the chain from source to output before suggesting any change. That keeps advice specific and avoids replacing equipment that was never the cause. Where a fix costs little, we say so plainly, and where it needs a change of procedure rather than hardware, we say that too.
