Named only 20ETS, this 72.2 KB PDF is filed under schematics and describes no specific device, board number or revision. As the base code of a series also found here with suffixes such as 08S and 16S, it may be a general reference for the family. Open it in any PDF program. Use it as a starting point to compare variants, check pinouts and confirm electrical limits. Then compare the exact suffix stamped on the part you are replacing before you choose a substitute.
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.