Hi! Is the unit new? Is it still under warranty?
We really can't help you much here, but my first suggestion to you would be to contact wherever you purchased the unit from and don't get off the phone until someone can answer your questions. If they volley the question over to the manufacturer, then do the same. If nobody gives you satisfaction, start complaining that you have a lemon, and are more than happy to talk to your local consumer affairs reporter (have their name handy) and tell your story to them, about how Phillips and, say, Wal-Mart (or wherever you purchased the TV from) wouldn't give you the time of day to help you out.
Believe me, they do NOT want to hear that. That will scare 'em.