The 2SD1829 is covered by this 154 KB PDF, filed under schematics although the name points to a discrete transistor datasheet. By JIS convention, 2SD parts are NPN bipolar transistors intended for low-frequency circuits. Technicians use such a document to confirm base, collector and emitter positions, absolute maximum ratings and gain class while testing with a meter or picking a substitute. Check the marking on the component against the number before trusting the data.
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.