Please describe the problem. Will it not turn on? Does it take a long time to lock on to the satellites?

I know the oldest NuVi units (gray squarish ones) had problems with the power button wearing out. Is this what you are referring to?

Also, I definitely know that my newer 3790T locks on to satellites much faster than my older 350 or 680 NuVis did. It always helps to NOT turn the unit on until you are out of the parking garage, and if the last used location was close by it will find the connection faster than if it was thousands of miles away. Even if thousands of miles away, however, if it has been turned on and locked onto a signal recently it will connect faster than if it has been turned off for a month.

My strategy is to turn it on and let it lock onto a signal while in the rental car bus. It then will lock on to signals within ten seconds for the rest of my trip.