MacBook Pro A2289 Not turning on, fluctuating current draw 0.03-0.1A at 20V repair

MacBook Pro A2289 Not turning on, fluctuating current draw 0.03-0.1A at 20V repair
Device	MacBook Pro A2289
Affects part(s)	Motherboard
Needs equipment	multimeter, soldering iron, soldering station, thermal camera
Difficulty	◉◉◉◌ Hard
Type	Soldering, Micro-Soldering"Micro-Soldering" is not in the list (Soldering, Teardown, Part replacement, Cleaning, Software, BGA, General) of allowed values for the "Repair Guide type" property.

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Problem description

This issue is often caused by a short to ground on a sub-rail, which can be accurately detected with a high resolution thermal imaging scan. Low resolution thermal imaging may not reveal the subtle signs of a small shorted component, making it a less reliable diagnostic method.

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Symptoms

• No power
• No fan spin
• All voltages missing

Solution

If the issue has a single, specific solution, provide it in this section and delete the sub-headers below. Otherwise, if there are multiple potential causes for the problem, outline the process of identifying the root cause and offer corresponding solutions below.

Diagnostic Steps

• Perform High Resolution, High Sensitivity thermal imaging of the entire system board.
  • Low resolution thermal imagers will likely not pick up the subtle temperature changes failures like this often present with.
  • The failure will often present as a component quickly heating up and cooling down in sync with the amperage changes; Occasionally, you will find a resistor heating up/cooling down in sync with the amperage changes.
  • The short is likely caused by something on the output side of the resistor.

Repair Steps

• Remove and Replace the shorted component based on thermal imaging findings.