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Lenovo g700 - No power supply

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  • Level 2  
    Hello

    The laptop had a damaged charging plug. was replaced. I have also measured the voltages at the point of contact with the motherboard are correct.
    The charger has been checked on another laptop and vice versa so I exclude it.

    The symptom is a complete lack of response to the power supply. The battery charging indicator or any warning sound is not on. Nothing squeals as in the posts already posted about this equipment.

    A request for advice may be some kind of fuse that could burn out when you snatch the socket or some other item that needs to be checked - replaced.

    BAMBI motherboard main board rev. 2.1
  • Computer-specific
    Plate designation enter.
  • Monitor spec
    This is a CD under Leonovo (Intel i3-i7 IIIgen.) P / nr. 69N0B5M10A01
    - Pegatron platform or something from Asus
    HM70 (Intel SJTNV) / sometimes HM76
    KBC IT8528E FXA
    stby TPS51225C
    GPU chip (N14M-GE-B-A2) GT720M

    Measure the stba and LDO voltages (see datasheet), see if it warms up?
    Then take care
    - if you have a small resistance after LDO (it powers the NCB and Power button) it's 99% KBC to exchange

    Similar to G500

  • Computer-specific
    Incorrect socket replacement could lead to various faults. You do not write anything about the behavior of the power supply - if it has a light / diode, it does not dim after connection.
    Measure the resistance + of the power supply socket in relation to ground to the beginning - there is no short circuit. If it does not have to plug in the power supply and measure the voltage - do you have those around 19V on the power supply socket.
  • Level 14  
    I have exactly the same problem
    TPS51225 warms up
    LDO3 - 3.36V to a mass of 3.4k Ω
    LDO5 - 5.19V to mass 23k Ω

    Maybe someone has a schematic of this CD or can send the page itself with the vicinity of TPS51225
  • Computer-specific
    Schema unavailable.
    Take the system off and give the appropriate voltage to the LDO pins from the service power supply and see what effect it has.
    Measure the resistances on the main transformer coils and pass along the keys.
  • Level 13  
    Hello. TPS51225 is in the Acerach M series, PM50 platform, it may be helpful in the diagnosis, because the BAMBI (G700) and DUMBO2 (G710, Z710) schemes are nowhere to be seen. By the way, the slaughtered nest in these models results in damage to KBC ITE8528E.
  • Level 14  
    I put in a new TPS51225 because I just had it at hand.
    There is no change, the laptop still does not react and warms up TPS51225
    I think, just like piotrp26, that the NCB is damaged, I will replace it and it will turn out, I just have to wait for the package because I do not have one.