Got a new ChromeCast for xmas but having massive difficulty with setup. I have a 32" Sony Wega TV (without an HDMI port) that is connected to an AT&T cable box. I have an HDMI to AV converter that has RCA connectors (3) and the HDMI slot + power USB. I have tried all kinds of plugin options but nothing is working for me to see the 'setup code' info on the TV screen. The app is installed on my Android Tablet and the CC is on solid white once the connection is made. Have tried resets, disconnect/reconnect power, etc. but not making any progress. Any help would be greatly appreciated.