Board-level help works best when you bring numbers. Before posting in this category, try to have these:
- Model and board number. The board number is printed on the board (for example 820-02016 on a MacBook Air M1). Boards differ between revisions, and so do the readings.
- History. Liquid, drop, previous repair, or did it just stop?
- Current draw. What a USB-C ammeter or a DC power supply shows when you connect power and press the power button. Note what it does over time: steady, stuck at a value, cycling up and down.
- Measurements on the relevant lines. Diode mode or resistance to ground on the main power lines, and voltages if it powers up. Say which lines and how you measured.
- What you’ve already changed. Components replaced, reballed, or jumpers added.
- Photos. A sharp close-up of the area under the microscope, and one of the whole board side so people know where you are.
You don’t need all of it to post. But a topic with readings gets answered much faster than “no power, what to do?”.
And remember the schematics rule: name the lines and the document, but don’t post the files.