Covering the 2SC3599, this 124 KB PDF is a discrete transistor datasheet even though it is filed as a schematic. By JIS convention a 2SC number denotes an NPN bipolar device for high-frequency use. Open it in any PDF viewer to look up pin assignment, breakdown voltages, current limits and electrical characteristics. Those figures are what a technician compares when searching for a cross-reference or checking whether a part was overstressed. Read the marking on the original component carefully, as small packages often use abbreviated codes.
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 @cyberlanelectonik. 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.