I just picked up a commercial grade LG 42LH260H (designed for institutional use). Whenever the TV is turned off and then on again, it reverts back to the TV input. My cable box is connected via the HDMI input, which means I need to manually change the input every time I turn on the TV. I can't fix via the standard menu and will probably need to access the service menu. Any help on how to fix would be greatly appreciated.