Bought a new Vizio E420i-A1 TV to use as an additional monitor for my Mid-2010 MacBookPro (Running Mac OSX10.8.4). Connected via HDMI cable and HDMI/Mini-Display Port Adapter (TeraGrand Brand), the TV messaged "Retrieving Data" then "No Signal." Purchased a new adapter (Belkin Brand) and now the message goes from "Retrieving Data" to "Not Support!"[sic]. I've tried every combination of resolution and refresh rate available on the MBP Display Preferences and get the same thing. At Apple's suggestion, I reset SMC and NVRAM/PRAM, same thing. I know the HDMI port and cable work (tested with PS3). The computer successfully connected to an LG TV last week. What am I doing wrong here?