Is it hooked up to an antenna? Or is the antenna on that one internal? Other than that, maybe that unit has a first time init. sequence as their earlier models did. On my GPS-II, II+, and III they all had to do a first time init. Turn it on, let it sit for a while. When it realizes it isn't acquiring, it will ask questions, then after you answer a few, it does a first time search. That's my only other guess. Karl.