MacBook Pro A1706 Not turning on, PPBUS G3H short repair

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MacBook Pro A1706 Not turning on, PPBUS G3H short repair
Device MacBook Pro A1706
Affects part(s) Motherboard
Needs equipment multimeter, soldering iron, soldering station, thermal camera
Difficulty ◉◉◉◌ Hard
Type Soldering


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Problem description

Repair of a common short on PPBUS_G3H on an A1706 MacBook Pro

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Symptoms

  • sub 20 ohms on PPBUS_G3H
  • Not turning on

Solution

Inject 1 V (increase if no reaction), watch for hot spots with thermal camera. Usually it's a bad tantalum capacitor. Measure PPBUS_G3H to Vcore coils (coils around CPU/GPU). If those measure under 1 Ω (0.3–0.8Ω) then you most likely have a direct 12 V short to CPU/GPU. On this board this situation is always a no-fix.

Example video: No Power — A1706 2016 4xTBT3 TB 13" MacBook Pro 820-00239

  • 0 V — PPBUS_G3HOT
  • Inject 1 V into PPBUS_G3HOT rail.
  • U7600 Dual MOSFET gets hot. Part number CSD58879Q3D.
  • Visual inspection of shorted component shows solder ball popping out the side of component. C7601 is also damaged.
  • Removed C7601, short still persists.
  • Removed U7600, short gone.
  • As of April 29, 2018 no donors available. Board not fixed.