not switching on after disassembled

A few things to check:

- The phone usually will not vibrate when being turned on unless it is plugged into a charge.

- If it shows no signs of life while being plugged into charger, try plugging it into the computer and use iTunes to see if it detects the phone as being turned on.

- Have you made sure not to put the longer screws in the 4 screw holes that are used to hold in the metal plate that covers the screen connectors?

- It is possible that the logic board in the phone has long screw damage which can prevent the phone from turning on properly. Though this is hard to find out unless you have a microscope at hand, if you did not put longer screws or overtightened them a lot then you don't need to worry about that.

- Also double check the power / volume cable is plugged in which is the horizontal plug near the horizontal plug LCD screen display cable. (Where the metal plate would be usually)