"iPhone 4 doesnt power / turn on after screen repair"に関する回答If you plug this phone into direct power not into your computer, Let it sit for a min, and try to use your Vibe switch does the phone Vibrate? Just by your discription I would be guessing that the phone is turning on but the LCD\Digi itself is faulty. It happens a lot. I would disconnect the 2 LCD Ribbon cables. Battery and all. Leave the small metal pieces off. Keep the board and all the other wires plugged in plug in your phone to a computer with ITUNES started on it and see if it detects the phone. If it does? the Screen you have purchased is bad and you will have to get a replacement. Let say it doesn't? I would be guessing you scratched a component, hit a board chip. Something that controls the Trigger for the phone to turn on. From your description of the problem that is the best I could say.
"black screen, fading apple-won't boot"に関する回答For reference for future Iphone users with this problem, This is a display issue and the LCD\Digi would have to be replaced or phone sent in for warranty.
"Is there any "warranty void" sticker in iPhone 4S?"に関する回答We are speaking of a Iphone 4s. GSM or CDMA they were all made exactly the same, All components and stickers match. There is no LQDM damage dot on any screw in the 4S Model of the Iphone. Only phone with a LQDM dot on the screw was the Iphone 4 ATT GSM. The tape under the rear camera will peal of easily so you can place it back on. I have repaired countless iphone 4s's and that sticker is no void indicator. They are not placed on exactly the same way on each matching device. Your warranty void would be the breaking of the seal of the back cover. That's all it would take. Pentalobe screws are placed in at a specific torque in specific ways. If you sent a phone back to apple if you open the back cover and put it back on they would be able to tell. As far as going to your local Phone shop with a phone under warranty after you dabbled around on the inside for a bit, as long as the liquid damage triggers are not red in the headset jack and or the System connector plug in, you would be fine.