Datasheet-style PDF of 87.7 KB labelled 2SC3400, listed in the schematic section of the index. In the JIS system a 2SC number identifies an NPN bipolar transistor designed for high-frequency work, so the document should describe one discrete component rather than a whole circuit. Repairers rely on it for pinout, collector-emitter breakdown voltage, power dissipation and gain class. It opens in a standard PDF reader. Make sure the part removed from the board really carries this number, as similar codes are easy to confuse.
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.