Apple logic board schematic for board number 820-3024, delivered as a PDF inside a compact RAR archive. Apple uses the 820-xxxx pattern for its main logic board part numbers, and the exact number is printed on the PCB itself. The schematic helps with tracing the power path from the charger input through PPBUS and the main rails, checking SMC signals and following why a board fails to power up. Match the 820 number on your board before using these pages, as similar models carry different circuitry.
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 @schematicslaptop. 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.