Not automatically a codec BGA pad
An open can be connector, filter/series component, trace, pad or IC-side. Locate the discontinuity before reball/jumper work.
IPHONE AUDIO / MICROPHONE / SPEAKER FORENSICS
Route the sound.
Route the sound.
Then prove the failed block.
Separate codec power, serial audio buses, microphone bias, speaker amplification, call/media routing and acoustic transducers before reballing a codec or replacing a flex.
AUDIO EVIDENCE CHAIN
POWER
CODEC
I²S/TDM
MIC/AMP
ROUTING
OUTPUT
Use function-by-function isolation: calls, speakerphone, media, Voice Memos, rear video, front video and panic evidence can point to different branches.
01 — AUDIO SIGNAL HIGHWAY
Trace the seven-stage audio chain
Each stage is independent evidence. A greyed icon or failed microphone is not enough to name the codec.
02 — SYMPTOM-TO-PROOF ENGINE
Codec, earpiece, mic, distortion and watchdog branches
Each case keeps alternative causes open until bench evidence narrows the subsystem.
SELECTED FAILURE
Observed evidence
Competing domains
Proof required
03 — CALL VS MEDIA ISOLATION
Use the app mode to identify the active path
Routing varies by model and software generation, so treat these as source-derived diagnostic branches rather than universal microphone numbering.
| Scenario | Source Mic Path | Output Path | Likely Domain if Only This Mode Fails | Best Confirmation |
|---|---|---|---|---|
| Cellular call — handset | Bottom / primary-call microphone branch | Earpiece receiver | Dock/lower mic, earpiece path, call routing/baseband-audio path | Compare speakerphone + Voice Memos + rear/front video |
| Cellular call — speakerphone | Front/top microphone branch in source | Top + bottom speakers | Upper mic/flex, speaker amp/output path | Compare normal handset call and media playback |
| Rear video recording | Rear-camera microphone branch | Recording only | Rear mic/flex or codec input branch | Compare Voice Memos and front video |
| Front video recording | Front/top microphone branch | Recording only | Upper mic/flex or codec input branch | Compare rear video and call modes |
| Media playback | N/A | Stereo speaker amps | Speaker amps, boost, speakers, codec output | Compare earpiece call + wired/Bluetooth if relevant |
Exact microphone numbering and routing can change by iPhone model. Use model-specific schematic/boardview and functional comparison before assigning `mic1/mic2/mic3` to a physical transducer.
04 — AUDIO REFERENCE DATABASE
Voltage + GR + resistance + bus state
Values below are retained as uploaded-source references, not universal Apple factory specifications.
| Subsystem | Rail / Signal | Source Voltage | Source GR | Resistance | Signal / State | What abnormal supports |
|---|
05 — LIVE AUDIO-LINE EVALUATOR
Combine GR, live voltage and functional mode
Passing one static checkpoint does not prove the complete audio path.
06 — SOURCE RULES CORRECTED
Do not let one audio symptom force a BGA repair
V2 deliberately removes several one-to-one conclusions from the uploaded V1.
Not automatically dock flex
Compare call, Voice Memos and front/rear video; then check bias, connector, transducer and codec input path.
Not automatically boost coil/cap
Test known-good speaker, inspect debris/water damage, then evaluate amp boost/ripple and load behavior.
Token first, exact model second
`mic1` can identify a telemetry domain, but physical location and flex mapping must be confirmed for the exact model.
Does not prove full audio integrity
Serial bus, AC audio, intermittent solder, connector and state-dependent faults may remain.
Do not inject arbitrary voltage
Only inject into a confirmed low-voltage rail within safe limits. Do not inject directly into speaker outputs, I²S or unknown audio nodes.
07 — AUDIO / MIC CASE DOSSIER
Record app mode, active path and confirmation evidence
Preserve call/media comparison, flex substitution, panic token and line measurements.