Dead iPhone 5

Iphone 5

Nothing comes on, no sign of life in it.

Tried:

- Hard reset ( home + power buttons)
- Holding the home button while connecting the data cable.
- Checked the connectors are popped in.
- Tried to connect it to itunes with the battery disconnected.

Nothing worked. Any ideas?

it's out of warranty.
I was asking in case somebody had this problem or has any idea how to fix it.
I've read someplace that it could be the dock connector or the battery. From my experience, iphones connect to itunes even without batteries fitted in. I suppose it could be the dock connector. I will try to find a charged iphone 5 battery first to verify if it's the dock that's faulty.
I'll be back with updates.