Change your Linksys WRT1900ACS AC1900 Dual-Band Wireless Router password? Visit linksyssmartwifi.com or http://192.168.3.1 Login Window will show on your screen. You can change the secret phrase subtleties with the entrance of the login page. Go to settings, select Management and afterward go to the Password on the left half of the web menu. Enter your current or default password (If not changed) and enter the new secret key you need to set.