IBM ThinkPad T61 schematic in PDF form, around 2.21 MB. The name states the model only, with no board number, revision or graphics variant, and T61 boards existed with both integrated and discrete graphics, so check the PCB markings carefully. Such a diagram is used to trace power rails, check enable and power-good signals, verify component values and identify the part shorting a rail. Any PDF viewer opens it, and text search helps find nets and reference designators quickly.
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.