The 2SB1221 transistor gives its name to this 50.0 KB PDF, which carries an _E suffix and is filed under schematics, but is most likely the component datasheet. In the JIS system the 2SB prefix marks a PNP transistor intended for low-frequency work such as audio and switching stages. The sheet should list pin assignment, package, maximum collector current and voltage, and power dissipation, all needed when replacing a burnt part. Check the marking on the original before choosing a substitute.
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.