I am using this as a monitor with a direct tv hd reciever. Has a nice looking picture but the actual video signal is larger than the screen size...in other words any writing at the bottom or top of the screen are cut off by maybe an inch or less. In the menu there are boxes to adjust screen size but cannot be accessed I am a former tech and know there is a key combination to access this....anyone know this or have a service manual for this model. It would be listed in the service manual. Thanks for any help you can provide.