Hi,
A big thanks to Levani_PMIC and also roro manool. I found an iPhone5 dead board and I removed that U3 IC and soldered. It was working for 20 mints then again the ON/Off button stopped working. But the Home button works well.
Then I removed the phone and checked that U3 and it was firm in the motherbaord. After I was reheating the board the IC which is down to U3 disappeared. Check the picture whch is marked in red.
Without that Transmitter/IC the phone is working well. I coudnt see any problems for now. Luckily the camera is also working.
I hope this thread helps someone.
Cheers