Part number 2SA1972 titles this 191 KB PDF; in JIS semiconductor naming, 2SA designates a PNP bipolar transistor. The file is filed under schematics but is most likely the datasheet for that device, and the name gives no maker, package or grade. Use the document for pinout and electrical limits when diagnosing a failed stage, and compare the package dimensions with the board footprint before installing an original or equivalent part.
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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)