Rick, I had a 6610 (but now I have a 3310). The 6610 kept shutting itself off at times. It's a contact problem. the switch is loose. Open up it's insides, change a battery or take the battery out and put it back in and see what happenes. Chances are it will be better. If not, live with it, I'm afraid. Only a specialist can fix it.
Geray, January 2008