PDF schematic for the Apple logic board 820-3023, packed into a 1.42 MB RAR archive. The name carries no revision letter, so confirm the suffix on the board before relying on part values or net naming. Extract it with 7-Zip or WinRAR and open it in any PDF reader. The drawings support tracing power rails, checking the SMC and charging sections, identifying test points and working out which component sits on a shorted line during logic board repair.
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.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
7-ZipWinRARThe Unarchiver (macOS)