I have a 13'' macbook pro 8.1, OS X and I read online that I can hook it up to my tv (a Samsung 55" LED) using a thunderbolt to HDMI converter so I bought a brand new one online and tried it out but it's not working! My tv doesn't detect anything and I tried several tvs and different HDMI cords and none of them detect my macbook. Am I missing something? Or is it a faulty cable?