The panel inside (and even the chasis) of the 660-650 are different from their higher end models.  Unfortunately, you didn't buy the highend model.  One of the various ways sharp saved money (and you saved money) is that your picture quality isn't as good, and your tv doesn't except discretes.  I have spent more time than you can imagine on these TVs, which I don't even carry.  Go high end or go rs232.