iPhone 4S will not power on, no damage or previous issues.

Hello all, I'm hopeful someone may be able to help. I plugged in my 4S to charge, came back 2-3 hours later and the screen was black. I tried to power it on with no reaction. Plugged it in and the apple logo appeared and then disappeared. It did this back and forth for awhile until I unplugged it, and when I did the apple logo went away immediatly. I thought the battery went bad, so I changed it with no luck. I then tried another battery, swapped out the charge port, checked connections, ect. All with no luck. I then plugged the phone in and held the home button and got the "connect to itunes" to come up and then connected to my Mac and itunes, but it doesn't recognize the device, i restored it and after leaving it plugged in for some time it did turn on. When it was on it was like the battery was disconnected, the battery showed 100% and it had no cell signal and no wifi. I went into settings to wifi and it did not show any wifi connections and the wifi on/off switch was mute. The device had not suffered any damage nor water damage and has always been kept in a military grade case. I am very familiar with the workings of iPhones and have made many, many repairs but this has got me stumped. Any help would be greatly appreciated.