I have had the 7710 for a few years now. Love it when it works. The mini USB port on the side had to be replaced once as it would not charge from the 12 volt car charger, the USB cable from the computer and the 110 electric plug cable.
On the last trip it again stopped charging again and I used my smartphone GPS app to get me through the trip.
As it is out of warranty, it costs $100 up front to get it fixed.
When Camping World had the Good Sam RNVD 7735 on sale for $249 I bought it. The new plug and cradle now has a right angle plug with a clip on the cradle to prevent the cable from hanging on the device.
Now I have been looking to see how I can replace the mini USB port and getting it to work.