The 2SC4108 is the only detail this 94 KB PDF name provides, and the index files it as a schematic. Japanese JIS/JEITA designations beginning with 2SC belong to NPN transistors for high-frequency applications, so a datasheet is the likely content. Repair use includes confirming base, collector and emitter pins, checking maximum voltage and current, and comparing characteristics when picking an equivalent. Open it in any PDF viewer and match the package type to the component fitted on the board.
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.