Listed as a schematic, this 166 KB PDF is named 28C65B, a variant code in the 28C parallel EEPROM family with a B revision suffix. No manufacturer or package is given. Expect pin assignment, supply and timing specifications and the write procedure. Technicians open it to identify the memory, select the matching programmer profile and judge whether a related 28C64 type could replace it. Confirm the suffix and pinout against the real chip before substituting, and back up the original contents first.
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.