Schematic PDF for NL6 BTM-D, apparently the undated release of the same design also found with a 2014 date stamp. The name lacks a brand, revision and board number, so match the title block with the markings on your PCB. Drawings like this list rail names, regulator parts, connectors and test points needed when diagnosing no-power or short faults. Any PDF reader opens it. If both NL6 versions are available, compare them to find which revision fits the board on your bench.
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 @ITHINKHS. 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.