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  1. #1
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    820-00840 not working from the battery

    I have the above which had mild liquid damage around the board which has now been fix and the logicboard is working but my problem is the battery.

    It will work with both the power lead and battery connected or just the power lead but if I pull the power lead out with the battery connected it turns off.

    In the OS it shows a percentage and say's it charging. If I go to system under power, it says that the battery is connected and charging. If I leave the power lead connected you can see the percentage going up.

    At first, after measuring around the board, what seems to be missing are the SMBUS_BATT_SCL, SMBUS_BATT_SDA and SYS_DETECT_L. So I thought it was the SMC, but with the SMC showing the correct information when it's in the system profile then, I've ruled this out for the time being. After more digging around I found that I was missing PP3V3_G3H on the battery alone. and to be more specific PM_EN_P3V3_G3H which comes from U7000. I replaced this, but it made no difference.

    So now i'm stuck, I know PM_EN_P3V3_G3H is created by U7000 but there must be something else externally that switches that on.

    One last thing I have noticed with just the battery connected PM_EN_P3V3_G3H if fluctuating between 0.3v-0.6v, PPBUS is showing 11.45v

    Any pointer in the right direction

  2. #2
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    Re: 820-00840 not working from the battery

    You will only have power if the BMU cable is 100% good.

  3. #3
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    Re: 820-00840 not working from the battery

    I'm presuming the BMU cable is the additional flex coming from the battery! This has been swopped for a brand new flex.

    Update - I've replaced the U7000 from a working board and also reballed the SMC form the same board - both didn't make any changes

  4. #4
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    Re: 820-00840 not working from the battery

    Do you have a known-good battery?

  5. #5
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    Re: 820-00840 not working from the battery

    Hi

    U6990 pin 10 is the enable pin 3 is swout
    All posts spelling grammar checked
    Regards Tellyman

 

 

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