Who I have the same questioned this topic

After about 2 months of working flawlessly my JP 5510L started shutting down on its own.  does not restart- have to reboot manually. It's kept plugged into the charger so not a battery life issue. Finally received a replacement yesterday that does the same thing. Software says it's up to date.  Setting is for it to never shut down as we also use it for wireless security cams when traveling. We're in a 3G only area BUT a previous JP we had never had this problem. Ideas, solutions all welcome.