Hello, I've had the Go 910 for years now and it's never missed a beat. I noticed the other day that I didn't get any voice warnings. I checked volume and that was ok. I tried to alter the voice itself and when I did I had the option to test and the test was ok, It warned that I had selected a human voice that could not read some warnings so I selected a computer voice instead ... but nothing happens when it is time to warn ??? Any clues about what to do?