Bought the 1605 in January 2013, was working more or less OK until half way through a 4 week road trip when it refused to continue past the " share info with TT " page. Cycle unit off / on several time to no avail. Finally left unit turned on for several days and it then started to function. But even when working it seems to get bogged down very easy and lags behind input commands. It is also very slow to lock into the satellites. When it is working correctly I am very pleased , but I fear that TT has sold me a lemon. Any suggestions.