PDF manual of 1.64 MB for a product named Rhos; the name gives no device type, model number or board identifier. Although indexed as a schematic, the word manual suggests a user or service guide rather than a circuit diagram. Open it in any PDF viewer to determine what equipment it covers and whether it includes technical specifications, wiring or troubleshooting sections. Check any model codes listed inside against the unit being serviced before following its procedures or relying on its values.
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 @oficinacomputadores. 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.