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820-00165 fan spins once

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  • 820-00165 fan spins once

    was bit water damage around smc R5180 R5179 replaced, it was working for few days, now came back

    -ultrasonic done, looks good actually

    -green light is ok on cgarger
    -fan spins once then dies
    -r7121 r7122 are ok 10ohm, that area is not water damaged
    - i can do smc reset
    -it powers on on for a sec, aftger that i can start it again with the power button, but after 1 sec it goes down, and takes 0.34A
    -when it powers on i can see 1.8V 1.05 5V, all of them, then the go away, but 8.59V 3.3V 3.4V remain, they are ok

    -i replaced the bios from a donor board to see if it stays on but does the same, so i put back the original bios

  • #2
    Liquid spill near SMC, so better to reball it.
    Try to start in SMC bypass mode.

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    • #3
      I agree try SMC bypass mode the SMC could have been damaged.

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      • #4
        yeah, in SMC bypass mode it turns on and there is picture

        i will try to leave it overnight in full alcohol, maybe it can remove some crap under the smc, if that wont work i will reball it it, and have some donor board to replace SMC if needed to

        thx!

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        • #5
          Check resistance between pìns 17/18 and 27/28 at U7100.
          Also post voltage for pins 9 & 15.

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          • #6
            Yeah sounds to me like an SMC issue.

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            • #7
              i reballed the smc, then replaced it from donor board, same exact issue

              powers on 0.5A, fan spins, than dies,

              its not smc,

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              • #8
                with new smc it powers on in smc bypass mode, same as the original smc

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                • #9
                  L5001 is corroded, that give 3.24V to SMC, there was no connection to C5001, i fixed it with a cable but still same, to measue if connects to under the smc i hav eto remove again the SMC.....

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                  • #10
                    What voltage do you get on PPBUS with just the charger when it spins once then doesn't turn on?

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                    • #11
                      u7100 9 and 15 pin both zero V

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                      • #12
                        PPBUS with only charger is stable 8.58V

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                        • #13
                          u7100 27/28 pin resistance 174ohm

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                          • #14
                            u7100 18/18 3.4ohm

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                            • #15
                              That's your problem then is 27/28. One of the the following is true:

                              1. R7121/2 is blown or both
                              2. R7120 is blown (possible but much less likely)
                              3. The traces from the ISL to R7121/2 are bad OR from R7121/2 to R7120 are bad.

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