Schematic diagram for the Lenovo ThinkPad T490s mainboard NM-B891, provided in a 2.71 MB RAR archive. The NM-xxxx designation follows LCFC numbering, the Lenovo-owned manufacturer of ThinkPad motherboards. Technicians use it to follow the power sequence, check rail voltages, read the EC and charger pinouts, and trace signals between chips. No revision is given in the name, so compare the PCB revision with the drawing header before relying on specific values, and pair it with a boardview for physical locations.
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 (9)
The same file was posted more than once. If one link is dead, try the next.
| Channel | Posted | |
|---|---|---|
| @schematicslaptop | 6 Mar 2021 | Open file on RM Schematics |
| @pepeelectronica | 21 Apr 2022 | Open file on RM Schematics |
| @pepeelectronica | 24 Apr 2022 | Open file on RM Schematics |
| @cyberlanelectonik | 18 Jul 2026 | Open file on RM Schematics |
| @schematics_bios | 24 Jul 2026 | Open file on RM Schematics |
| @schematics_bios | 24 Jul 2026 | Open file on RM Schematics |
| @schematics_bios | 31 Jul 2026 | Open file on RM Schematics |
| @schematics_bios | 1 Aug 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.