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Samsung S7 G930F No power up. Dead

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  • Samsung S7 G930F No power up. Dead

    Samsung S7 GOLD DEAD(received as dead handset in good cosmetic condition no evidence of water damage)
    Original observed behaviour DCPS 0mA B4 PTB, PTB 70mA release power button back to zero
    Several replacments of PMIC has left the behaviour unchanged

    Bad board
    DCPS 0mA before PTB
    DCPS PTB 60-70mA. Remove tweezers from power on pins drops back to zero
    1. Main power rail IS present
    2. Power on signal (PWR_ON)from power button press present
    3. Power On - AP_PS_HOLD 1.8v?✘
    4. No PMIC voltages
    5. The seated resistance on the main power rail as compared to known good checks ok.

    known good board
    1. PWR_ON (4.0v) and AP_PS_HOLD (0v ->1.8v)
    2. AP_PS_HOLD 1V8 persists
    3. AP_PS_HOLD 1V8 inputs to both PMIC and CPU.
    If AP_PS_HOLD is not present the phone does not boot.

    Am wondering whether this could be a case of dead CPU rather than dead PMIC

  • #2
    We are very quick to use CPU swap as a diagnostic tool for Samsung board because there is less information on them and the boards are inexpensive and CPU swap is straightforward. In our experience s7 CPU swap does seem to solve a number of these that have this presentation, which means that the CPU isn't usually dead. However we've never gone back to the original board to try and determine the original fault--which may be solved just with heat on the CPU, we don't know.