The largest of this group at 465 KB, the PDF named 2SC4394 is most likely a full datasheet for that transistor rather than a board schematic, despite its index label. Following Japanese JIS rules, 2SC marks an NPN bipolar transistor. The name lists no maker or package. Repair use includes confirming base, collector and emitter pins, checking safe operating limits and reviewing graphs before swapping the part in an amplifier or power circuit. Match the suffix and case style of the fitted component.
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.