Question / Claim
Why do MacBook Pro 2017 speakers work only after plugging and unplugging headphones?
Key Assumptions
- The MacBook Pro 2017 uses a single audio IC to control speakers, microphone, and headphone jack.(high confidence)
- The audio IC has degraded solder connections that prevent proper initialization at boot.(high confidence)
- Plugging headphones triggers a hardware interrupt that can temporarily restore the IC connection.(medium confidence)
Evidence & Observations
- Internal speakers are not detected in Sound settings on boot.(personal)
- system_profiler SPAudioDataType returns an empty device list.(personal)
- Audio works temporarily after plugging and unplugging headphones.(personal)
- Thermal cycling in thin BGA-mounted ICs is a documented cause of solder fatigue (IPC-9701 electronics reliability standard).(data)
- Independent Apple board-level repair technicians (e.g., Louis Rossmann Repair Group) have documented widespread MacBook Pro 2016–2017 audio IC failures linked to heat stress.(citation)
- Repeated real-world repair cases show audio IC revival when mechanical stress or localized pressure is applied near the chip, indicating cracked solder joints.(data)
Open Uncertainties
- How long the temporary revival will continue before complete audio failure occurs.
- Whether heat or physical stress accelerates the IC solder degradation.
Current Position
The speakers work after plug-in/plug-out because the failing audio IC chip is temporarily reinitialized by the headphone jack interrupt, allowing short-term audio functionality.
This is work-in-progress thinking, not a final conclusion.