I'm just posting this for reference since I've read that another person had this same issue. When I powered on my TEAC AG-H380 its screen would briefly display "DAB Mode" and then "Resetting" and get stuck like that.
Here's the solution:
Turn the unit off with the remote so that it goes to sleep (you should still be able to do this even though nothing else works). When the unit is asleep (i.e., the LED is orange), hold down SOURCE and the PLAY/PAUSE button until the unit resets. Yes, this is just the normal factory reset key combo from the manual, but in this case you have to do it while the unit is asleep. It won't work while it's on and stuck "Resetting."