Schematic in PDF for the Samsung Galaxy S3 variant identified as I9300i, the dual-SIM version of the phone. The document, about 2.9 MB, should show the circuit diagrams for power management, charging, RF and peripheral sections. It is useful for tracing rails, locating faulty components and checking lines between connectors and chips when a handset does not power up or charge. Confirm the model on the phone label is I9300i, as the standard I9300 uses a different 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 @mobileshematic. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.