In case anyone else can benefit, I partially answered my own question.

If the tuner doesn't detect an OTA digital signal it will automatically switch over to analog search. It then stays in analog mode. I tried unhooking my antenna and then plugging it back in. The only way I could get the digital channel to show up was by switching the channel. Makes it pretty useless for antenna adjusting when there is no signal to begin with unless there is some way to prevent the TV from using analog at all.

Still no idea if there is a built in FM trap.