PDF datasheet, 48.1 KB, for the part named 1T3797, indexed among schematics. The 1T prefix follows the Soviet designation pattern used for germanium transistors, though the name states nothing beyond the part number. Technicians use such sheets to identify leads, check permissible collector voltage and current and read gain values when repairing older equipment. Because unusual numbers are easy to misread on worn cases, confirm the marking on the actual component matches this type 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.
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The standard format for schematics, block diagrams, power-sequence charts and service manuals.