The first step checks the power suppliers, whether the phone is dead in the Hw or Sw. How:
Connect the cable from the power supply connector to the battery of the phone at least 3 cable, the order negatip, BSI and positive. (black, green and red) - Navigate volt power supply at 3.6 V (or in accordance with its HP-tolerance 0.5 V). In the mobile phone off, press the keys on. When the ampere when the button is pressed on, it still means that there is a problem on its hardware (HW), the checks need to be components of the on / off until the battery. When the ampere when the button is pressed on, ride around - + 50 mA, then the problem is happening is a problem the software (SW), then the need to do is re-programmed phone (flash) program or upgraded to a higher version.
Power Supply:
