For what computer brand and model? Is it a desktop or laptop computer? This is basic info that should accompany every request in this forum. I could find you plenty of AD1986A SoundMAX drivers but most likely they won't work unless they were designed for your specific computer brand and model.
Open Device Manager, find and double-click the sound device, click the Details tab, select "hardware id" and give me the hardware id string that begins with "PCI\VEN", (1st./top line of text only).