Iphone 4S bootloop

Hello,

So I tried to repair an iphone 4s with some sort of "bootloop". It restarts every 3 seconds... ( https://www.dropbox.com/s/djk0eclmz4ognz... ).

I changed the Dock connector, I tried a new battery and tried to restore with DFU (error 4005).

Could someone help please, I am out of solutions...

Thanks

Michael