Schematic in PDF format for the IBM ThinkPad X61, about 1.42 MB. The file name carries no board number or revision; it appears to be the same size as another X61 schematic in this index, so it may be a duplicate copy. Check the PCB markings before relying on it. A schematic like this is used to follow power rails, check the startup chain, verify component values and trace a short to its source. Any PDF viewer opens it, and searching net labels makes navigation quicker.
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 @alischematics. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.