Here is a 151 KB PDF for the 2SD1230, filed under schematics although it relates to one transistor type. Under the Japanese JIS scheme, 2SD means an NPN transistor for low-frequency use. The name gives no further detail, so the document itself should be checked for package and rating information. Typical sheets include breakdown voltages, collector current, dissipation and hFE groups. Use them for meter testing, pinout confirmation and choosing an equivalent with at least the same voltage and power capability.
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.