Reference PDF of 114 KB for the 2SK1691 N-channel field-effect transistor, the 2SK code being part of the Japanese semiconductor registry. Only the part number appears in the name; maker and package are unstated. A technician would use it to confirm which pin is gate, drain and source, check breakdown voltage and drain current limits, and evaluate cross-reference candidates. Compare the body marking and package of the removed part with the drawing before relying on these specifications.
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.