Providing a full schematic for the is challenging because the manufacturer does not publicly release service manuals. However, here is the proper content and known sources you can use to find or request it:
In the "Golden Age" of electronics, manufacturers included schematics inside the box. It was expected that the user might want to tune the coils or replace a capacitor. Today, the D-808 is a black box. xhdata d-808 schematic