A small 44.6 KB PDF named 2SC5310, filed under schematics though the title is a transistor part number. The JIS 2SC prefix marks an NPN bipolar transistor, so this is likely a short datasheet or summary sheet. Its compact size suggests limited pages, perhaps ratings and a package outline only. No manufacturer or device appears in the name, so confirm the part marking. Use it to check pinout and basic limits before replacement, and consult a fuller datasheet if detailed curves are needed.
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.