Schematic of a 5-band graphic equalizer in a small 16 KB PDF, with a YMYA tag in the name that may refer to the source or the designer. No chip numbers or band frequencies are given in the title. Diagrams like this show the gyrator or LC band filters, the slider potentiometers and the op-amp gain stages, which helps when tracing a dead band, a scratchy slider or a hum problem. Any PDF reader displays it. Compare the parts and pot values with the actual board before relying on the drawing for repair work.
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 @pdf_servicemanual. 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.