Schematic in PDF format, about 3.46 MB, for the Apple logic board 820-03286. It is listed alongside related boards 820-03160 and 820-02536 in the index. Apple 820 numbers identify the logic board rather than the computer model, and the number is silkscreened on the PCB, so check it first. The diagram supports tracing rails from the input stage through each regulator, confirming enable and power-good signals and looking up component values when replacing parts. Pair it with the matching boardview to locate 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 @cynetitsolution. 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.