ZIP archive of 1.48 MB for the Apple logic board numbered 820-3536. The name states no revision or content type, so it could be a schematic, a boardview or a mix of service files. Apple's 820 numbering identifies a specific logic board design, and revision letters can change details, so verify the marking on the PCB. Extract the archive and open the PDF in a viewer, or any board file in OpenBoardView, to locate rails, measurement points and faulty components.
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.
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