Schematic PDF, 1.16 MB, named Tin Yat 80A. Tin Yat appears to be a project code name, with 80A as a variant or revision marker, though the name does not state a brand. Open it in any PDF reader and check the title block for the board number before use. The diagram shows power rail generation, charger and regulator circuits, and the connections between the main chips. Technicians use it to find faulty sections and expected voltages during repair.
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 @cyberlanelectonik. 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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)