A short 64.3 KB PDF titled after the 1KAB-E series, catalogued as a schematic but by its name more likely a datasheet covering a family of discrete components such as rectifiers. The title gives no device or board number, so check the first page to confirm what parts it describes. Sheets like this list maximum ratings, electrical characteristics and package dimensions, useful when identifying an SMD marking or choosing an equivalent part during a power-circuit repair. Any PDF viewer opens 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.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.