"If you have replaced battery and dock, Fast battery drain, red screen, and sudden death are all very good indications of a short.
More often than not the short is the tristar IC (1610A2), which becomes damaged from using cheap wall chargers, car chargers, ipod docks, ect.
The issue is board level, and its impossible to know if the issue is this ic or something else on the baord. Your best bet is to send it to someone for board level diagnosis or repair. There is a link on my profile to a website that will help you locate some of the most trusted board level techs there is. There may even be one close to you. If not, all of them accept mail in repair.
Sudden death on the iPhone 6 series is common, and it can almost always be fixed, but only by experienced board repair technicians. I fix many of these each week"
"I held down the phone's right hand side power button and the front home button at the same time, for about ten seconds. Then the Apple logo came back on the screen, and after a few minutes I was able to redo the set up process. I had tried that previously without success, but I hadn't held the two buttons down for long enough - it took about 10 seconds before the phone eventually responded.
Good luck, I know how frustrating problems like this can be!"
I’m using Iphone 6+. I can’t turn on even I hold the button of HOME and POWER ON/OFF for 30 seconds while it’s charging of course. Even I clean the chord or my iphone or holding buttons everywhere nothing works. But it really works 100% it needs HEAT. I put it in under my laptop when it overheats and then tadaa it opens. I don’t have hairblower, radiation something, don’t have a car, and worst I don’t want to put it in a microwave or stove just to heaten the back and the front of my Iphone 6+. But the problem is if I unplug the charger of my iphone and then it goes to back to the logo of One Red bar logo charging something like that. My battery was drained for 51% and needs to replace a new battery. I was really stupid for using my iphone while playing so don’t be stupid as me. But I’m telling you it really works it needs HEAT and if you want to fixed it instantly you just buy another new battery that’s all.
