PDF of 214 KB for the 2SC3328, an NPN bipolar transistor under the JIS naming system, catalogued here as a schematic though the content is likely a datasheet. Look for maximum ratings, hFE groups, saturation voltages, curves and the case drawing. No maker or device appears in the name, so verify that the part code and package match what is on the board. It serves for pinout confirmation, out-of-circuit testing and cross-referencing replacement transistors.
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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)