The 2SA1942 is covered by this 186 KB PDF, filed under schematics though it most likely contains the part datasheet. The 2SA prefix places it among PNP bipolar transistors in the Japanese JIS designation system. Data a repairer would look for includes the pin layout, package outline, absolute maximum ratings and hFE ranks, all needed when testing or substituting the device. The name gives no manufacturer, date or revision, so match the marking on the fitted part first.
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.