PDF datasheet for the EL1604, filed as a 64 KB document; the name gives only the part number. Parts with the EL prefix were made by Elantec, a maker of high-speed analog ICs such as amplifiers and line drivers, so the document likely describes such a device, but confirm the function on opening it. Use it to identify pins, supply limits and typical application circuits, and compare the markings on the board's chip with the datasheet before testing or ordering a replacement.
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 @datasheet. 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.