Hey, sorry to revive such an old thread, but it's still one of Google's top hits and it was one of the threads that helped me get mine sorted (after pulling info from several sources). I made a fairly comprehensive troubleshooting DIY video as I went through all the advice on what to look for and just wanted to share it here as it's sure to help someone along the way! Thanks to all those that went before me and offered solid advice!
https://youtu.be/xntJKWZpFac