Schematic PDF for the DXA 1802, size 1.63 MB, matching the name of an Ahuja public address amplifier model, although the brand is not stated in this name. The file is the same size as a separately listed Ahuja DXA 1802 document, so it is probably the same drawing. Use it to trace the supply, driver and output stages, check part values and find likely faults. It opens in any PDF reader. Check that your amplifier's board version matches before swapping components.
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.