A 238 KB PDF identified solely as 2SC5106, placed among schematics but in all likelihood the datasheet for that part. Japanese JIS naming uses 2SC for NPN bipolar transistors, with the body often stamped C5106. Expect pin configuration, package dimensions, absolute maximum ratings and typical characteristics inside. Check the package on the board against the drawing before relying on the lead order, and compare ratings carefully when choosing an equivalent from another manufacturer.
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.