Galaxy S3 keeps restarting
About 2 months ago, my Samsung Galaxy S3 took to restarting repeatedly. I did a factory reset, but this didn't help. So I read the threads on this which suggested restarting the phone in SAFE mode to ensure it wasn't a 3rd party app causing the problem. Within 3 minutes of the restart it had turned itself off and on again. So I again restarted in SAFE mode, and again within 3 minutes it had turned itself off and on again.
Whenever this happens, the battery meter shows missing sections, so I tried a different battery in case it was faulty and inconsistent power to the phone was causing a power drop which triggered the restart. No improvement, and it continued to restart every 3-5 minutes.
I really don't know what to do next except sell the phone on ebay as faulty (although it probably isn't) and buy something else. Maybe an operating system upgrade / downgrade would help? I'm currently running Android 4.3, kernel version 3.0.31-2168382, build number JSS15J.I9300XXUGMK6.