Apple schematic for logic board 820-01958, revision A, with the project code X1783 and the MLB-TKSB label shown in the name. The PDF sits inside a RAR archive and opens in any PDF viewer. Apple uses 820-xxxxx numbers for logic boards, so verify the number and revision on the board itself before following it. Technicians rely on such diagrams to trace power rails through the startup sequence, see which chip enables which supply and check expected voltages when a Mac shows no power or no boot.
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 | 25 Jul 2023 | Open file on RM Schematics |
| @cyberlanelectonik | 23 Jul 2026 | Open file on RM Schematics |
| @schematics_bios | 14 Aug 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.