This 50.1 KB PDF, labelled 30SCLJQ030 and catalogued as a schematic, most likely documents one discrete rectifier rather than a circuit board, based on its part-number style. It is the 030 grade of the SCLJQ family found elsewhere in this index. Use it to look up forward drop, reverse leakage and package dimensions when sourcing a replacement for a failed diode. Before fitting a substitute, compare its markings and ratings with the original part and confirm the internal pin configuration is identical.
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.