Component sheet covering the 3N254, delivered as a 42.2 KB PDF and indexed as a schematic. JEDEC numbers beginning with 3N denote registered devices having four leads. The file size matches other 3N25x entries, suggesting one datasheet that lists several grades side by side. Repair work benefits from it when checking pinout, maximum voltages and package dimensions for a replacement. Any PDF viewer handles it; read the specific row for 3N254 and verify the device marking on the board 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.