Schematic in PDF form for the Apple A1989 logic board, number 820-00850 revision A, compressed into a 7.76 MB RAR archive. Apple identifies its main boards with 820-prefixed part numbers, and the revision letter matters because component placement and values can change between revisions. The schematic is used to follow power sequencing, check rail names and trace signals back to their source while repairing no-power or no-boot faults. It works best alongside a boardview for the same board, and the PCB marking should be checked first.
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.
All sources (3)
The same file was posted more than once. If one link is dead, try the next.
| Channel | Posted | |
|---|---|---|
| @schematicslaptop | 4 Nov 2025 | Open file on RM Schematics |
| @cyberlanelectonik | 4 Jul 2026 | Open file on RM Schematics |
| @schematics_bios | 27 Oct 2026 | Open file on RM Schematics |
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.