Schematic set for a board identified as AB540, delivered as a 1.47 MB ZIP archive that, per the name, contains a PDF. Any PDF reader opens the extracted drawing, and text search makes it easy to jump to nets, reference designators and connectors. Use it to trace power rails, check the standby and main supply sequence, and find the part responsible for a short. The name gives no brand or revision, so confirm the PCB print matches AB540 before relying on it.
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 .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip