It was just a 'maybe' thought, but doesn't sound like it. What I might try is to hold in the reset button for 5 seconds, then see if that cures it (you will have to reset everything, but only once if it works). The reset button is in the top left corner of the unit. You will need something small to get it (like a toothpick or similar). Anytime I've had probs, I use a reset and everything has seemed to be okay afterwards (except the aggravation of haveing to put all my own settings back in). Past this, I'm sorry, I have no other ideas. Good luck.
hg