Not heard of any issues with this chassis, I'm not in a DSO area but I have heard of issues with some Sanyo and Philips LCD chassis in some DSO areas
Try holding down both the vol+ and vol- buttons on the set for 10 seconds, the menu will appear then the set will restart and it should take you to the welcome screen.
Don't discount the aerial though as the signal is tapped off from inside the analogue tuner to feed the digital tuner, if the signal is borderline you may miss some channels. Remember with an external digibox you're feeding the digital tuner first. That Philips digital tuner is an older design and not the most sensetive.