Compressed RAR file for Apple board 820-1573, about 1.31 MB. The name gives only the board number, with no drawing number, revision or content description, so open the archive to see whether it holds a schematic, boardview or both. Apple uses 820- numbers for its logic boards. Such documentation helps trace power rails, find components and test points, and isolate shorted parts. Read the number printed on the PCB and check that it matches 820-1573 before using any values or locations from this archive.
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 @Mac_Shematic_Santale. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.