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A1502 820-4924 restarts all the time when power on after liquid spilled repair

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  • A1502 820-4924 restarts all the time when power on after liquid spilled repair

    having 2015 a1502 820-4924.
    machine came in with no power at all,liquid spilled. ultrasonic cleaned and replaced most heavy spilled components.

    power back on already, hear the chime, then restarts,chime , then restarts, chime then loops....feels like the P+R+COMMAND+OPTION reset thing going on all the automatically.

    tried disconnected keyboard and touch pad, same
    onoff_smc =3.3v
    ws_kbd_onoff_l=3.3v

    voltage on pin 1,2,3 are 0 on J4813(keyboard connector)
    diode mode on them are all around 400+

    so I replaced U4850, same stuffs.
    doubted corrosion under U4820 and U4830, flux and heated , but same stuffs still

    any suggestions please?
    thank you!

  • #2
    Is the SSD plugged in?

    Comment


    • #3
      Could be corrupt OS, so remove SSD. Could be 100 other corroded things too......

      Comment


      • #4
        it actually restarts before it loads the OS , I tried another SSD already,but same story.

        Comment


        • #5
          Originally posted by roy.ruan View Post
          having 2015 a1502 820-4924.
          machine came in with no power at all,liquid spilled. ultrasonic cleaned and replaced most heavy spilled components.

          power back on already, hear the chime, then restarts,chime , then restarts, chime then loops....feels like the P+R+COMMAND+OPTION reset thing going on all the automatically.

          tried disconnected keyboard and touch pad, same
          onoff_smc =3.3v
          ws_kbd_onoff_l=3.3v

          voltage on pin 1,2,3 are 0 on J4813(keyboard connector)
          diode mode on them are all around 400+

          so I replaced U4850, same stuffs.
          doubted corrosion under U4820 and U4830, flux and heated , but same stuffs still

          any suggestions please?
          thank you!
          change the key board connector on board / try without key board see if its restart

          Comment


          • #6
            I tried without the keyboard already, same stuffs. check the connector carefully couple times , it shouldn't be the issue, i check voltage on ONOFF_SMC, not low ,so nothing to do with the connector shorting it to GND

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            • #7
              Corrosion somewhere. I had one with a similar issue and there was corrosion in the CPU Vcore power supply area. But it could be so many other things. Inspect carefully for corroded resistors and traces.

              Comment


              • #8
                Now I regret about the Ultrasonic process,really makes it way harder to find. so many areas got spilled for this one. seems like no regular routines can go and check by multimeter,will just look around otherwise just give up if nothing found

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                • #9
                  Originally posted by roy.ruan View Post
                  i tried without the keyboard already, same stuffs. Check the connector carefully couple times , it shouldn't be the issue, i check voltage on onoff_smc, not low ,so nothing to do with the connector shorting it to gnd
                  remove the connector , there is short inside connector, then try

                  Comment

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