Schematic in PDF format for Apple logic board 820-1550, compressed into a 1.34 MB RAR archive. Only the board number is given, with no model name or revision. Apple's 820 part numbers are printed on the logic board, so check the marking before using it. The schematic shows the power architecture, rail names, enable signals and connector pinouts. It is the main reference when you work out why a machine will not power on or charge. Pair it with a boardview for the same number to find parts physically.
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.