PDF schematic for the IBM ThinkPad R31, around 1022 KB. No board number, revision or hardware variant appears in the name, so identification rests on the model alone. Engineers use these diagrams to follow power from the adapter input through every regulator, verify enable signals during startup and locate components tied to a shorted rail. Connector pinouts are also documented, which helps with keyboard, display and port faults. Any PDF reader works for viewing. Check the PCB markings against the document first.
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.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.