Hey guys
i'm using iphone 6 on ios 8.4
for weeks, my screen has been smashed as I'm waiting for the repair guy to come back from holidays.
Over the last few days the screen started behaving oddly. Would become non responsive and only worked if phone was locked and unlocked again (restarting springboard in jibber jabber lingo)
Tonight the screen went completely dark while i was using the phone and would not come back to life. Lights there but no ones home.
Tried forced recovery, nothing. screen totally blank except for tell tale sign of light in form of a very faint shadow.
so i connect to itunes via usb. Screen still blank but windows 7 recognized the device and started itunes. As soon as itunes started, the phone started emitting the iconic "bong" noise every 2 seconds.
No screen, the mute button does't make the phone vibrate when switched on but the phone then starts 2 short vibrations every couple of seconds.
Which leads me to this google search result and ultimately here.
I really think its your screen. My phone has no reason to behave like this except for the totally smashed and barely usable screen. I think some connector of mine is damaged and in your case simply (hopefully) not plugged in right.
Will be replacing my screen in next 48hrs and see if that's all it is. Apples way of letting you know the digitizer and/or lcd is gooooone. :(