Three weeks ago had to get a replacement S5 because of a bad microphone. Last night, this new S5 which has been working fine, started acting up. I turned off the screen via the power key and couldn't get the screen back on. When I pressed the power or home button the screen would quickly blink a greenish rectangle then go dark again. The captive buttons light fine, the phone was functioning because I could hear texts and stuff come through. On a battery pull, it would boot up but no logo or screen. Just the green flash. I was able to get it to come back on after about an hour with repeated light taps of the phone. But after a few minutes screen would crap out again. But since the last tapping of the back it's been working for about ten hours now. I guess the screen has a slight short somewhere. Tmobile over nighted another S5 free of charge even though it's 6 months old. Much easier then dealing with Samsung directly.