I purchased a refurbished (wifi only) model. The problem occurred from day .
The system will freeze after about 5 minutes and sometimes simply reboots, even when it's not being used.
I have done a factory reset and booted to safe mode but problem persists.
I think it is a hardware issue, but what should I look for or tell a repair tech?
Boy, this thread got sidetracked quickly. Mostly because you asked a REALLY IMPORTANT question. Once it got sidetracked, no one came back to address your original concern.
So here is what I know.
1. If your system becomes unresponsive - meaning any icon you tap on nothing happens, even when pressing the big button in the bottom center - tap the power button. It shuts the sceen off. Then hit the oval button, unlock the screen. It should work.
2. The random reboots probably means something has been changed or knox has been tripped. Possibly the device may have been rooted/unrooted once. It probably is a google thing. I personally HATE google+. Try to clear the davlik cache. It is located in /data/dalvik-cache - in the root area, if using Total Commander. You have to have root. Delete everything in this directory then do an immediate restart. On restart, android will rebuild each caching file for each current app, it may take a minute or two, but there will be a progress message all along.
Try those things
