A 167 KB PDF identified only by the 2SD2481 part number, which points to the datasheet for that transistor rather than a board schematic. Under Japanese JIS rules, 2SD denotes an NPN bipolar transistor intended for low-frequency service. Use it to confirm pinout and package, check the maximum ratings against the circuit's operating conditions and evaluate replacement parts. When testing in circuit, compare diode-mode readings with the NPN junction layout. Match the case marking, usually D2481, before relying on it.
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.
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The standard format for schematics, block diagrams, power-sequence charts and service manuals.