PDF reference of 116 KB for the CA3306, a CMOS flash analog-to-digital converter in the Intersil and Harris CA-series line. Catalogued as a schematic, it is most likely the datasheet with pinout, timing and reference connections. Technicians use it to identify reference, clock and data output pins, check supply and reference voltages, and judge whether a fault lies in the converter or in the analog front end. Verify the exact suffix and package against the chip on the board.
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.