Schematic in PDF form for the IBM ThinkPad R40 laptop, roughly 1.45 MB. The file name gives no board number or revision, so compare page headers with the markings on your motherboard before trusting part references. A circuit diagram like this helps follow power sequencing, find the source of a short on a main rail, and identify resistor, capacitor and MOSFET values around the charger and CPU regulators. Any PDF reader opens it, and text search on net names makes tracing signals between pages much faster.
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 @cyberlanelectonik. 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.