The 2SD1061 is the subject of this 102 KB PDF, placed in the schematic section though it reads as a part datasheet. JIS designations starting with 2SD belong to NPN transistors for low-frequency applications such as audio and power stages. Use it to check how the leads are arranged on the package, the safe voltage and current limits, and typical characteristics. When choosing a substitute, match polarity and package and never pick one with lower ratings than the original.
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.