Fifth numbered sheet from the Sony K700 schematic set, a 424 KB PDF. Its exact section is not given in the name, so check the page titles inside and match them with parts one to four. Schematics like this guide board-level repair, showing how rails and signals connect between ICs and connectors, which lets you trace a fault, find test points and pick replacement parts. View it in any PDF reader and verify that the board revision on your phone matches the document.
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.