Audio section of the Samsung SM-A20S schematic covering microphone, loudspeaker and earpiece circuits, a 4.63 MB PDF. It shows the mic bias and signal lines, the speaker amplifier output, earpiece connections and filtering components. Use it when callers cannot hear the user, the loudspeaker is silent or distorted, or the earpiece gives no sound, tracing each path from the codec to the transducer. Any PDF viewer opens it; check the device model before using component references on the board.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @phoneSchematics. Enginerys does not host this file.
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The standard format for schematics, block diagrams, power-sequence charts and service manuals.