Part-number named PDF, 205 KB, for the 2SC5142 transistor; though catalogued as a schematic, it is likely the manufacturer datasheet. Under Japanese JIS rules the 2SC prefix means an NPN bipolar transistor. The file name gives no package, brand or revision. Such a sheet is handy for confirming collector-emitter voltage, collector current, dissipation and pinout before fitting a replacement in a power supply, deflection or driver stage. Check the original part markings and suffix letters before choosing a substitute.
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.