I have a sharp aquos 70 inch and when the tv has been off for a couple hours and I turn it on it works fine and has no issues. After a couple hours it has a random screen flicker line at the very top of the display but the tv is still watchable only on game mode. On other modes it has some freezing throughout the screen. Could this be possibly be due to a clog with the airflow to cool the boards on the tv? Any advice would be appreciated.