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Apple macbook pro A1398 not posting?

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    #21
    Re: Apple macbook pro A1398 not posting?

    Interestingly i got tge laptop to post but as follows.
    Disconnect battery.
    Connect the charger (laptop turns on but no post)
    Hold shift+power btn until the laptop turns off.
    Then press the power btn and it is posting.
    This procedure never work if connecting the battery. So i am suspecting the battery or its IC.

    And i have no clue what the shift key do in contribution to get the laptop to post!!!

    Nevertheless, the laptop was stuck at apple logo. And what is very weird ( There was no chime sound even when the laptop posted))

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      #22
      Re: Apple macbook pro A1398 not posting?

      Originally posted by AuroXad View Post
      Okey, so I pushed forward with my problem. I found a SMC Bypass method where you have to disconnect battery and charger, then press and hold power button for 10sec and while holding plug in charger and still hold while systems starts. My computer started to chime and booted successfully, but there are other issues. You should try this method also
      Can you please check the diode measure of the GPUVSENSE_IN signal?

      I am suspecting the GPU and would appreciate if you can tell this value.

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        #23
        Re: Apple macbook pro A1398 not posting?

        My board is A1465, without dedicated gpu. We have very similar problem. I tried to update macOS and also get stuck at apple logo, no chime before that. After reset i get error that checking firmware failed. Also without smc bypass laptop don't post and shuts off after exactly 35sec and turns back on automatically and loops like that. I'm suspecting bad efi, i ordered chip programmer and will try to reflash. Also i heard that bad serial number prevent apple laptop from booting and in my case when booted in successfully, there are no serial number, also i can't run apple diagnostics because of missing serial number.

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          #24
          Re: Apple macbook pro A1398 not posting?

          Originally posted by Weelcup View Post
          thanks for the update.
          I have already tried this but holding the pwr btn 10s and keep holding it while connecting the charger, it does noting. Even the charger led never turned on. Then keeping the charger connected and releasing the pwr btn kicks on the fans at highest speed and surprisingly no led indications on charging tip.

          However, with just connecting the charger, the led comes on and the fans build up speed gradually.

          Both scinarios no post.
          When i turn on my laptop with smc bypass method charger led won't turn on also, so it's normal. Also i think it get's in limp mode, because fans turn max speed and computer is slow.

          Even more ;D
          When I disconnect trackpad with keyboard fans also start build up speed, when connected back fan is idling again, so check that.
          Last edited by AuroXad; 08-24-2020, 04:46 PM.

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            #25
            Re: Apple macbook pro A1398 not posting?

            Originally posted by AuroXad View Post
            When i turn on my laptop with smc bypass method charger led won't turn on also, so it's normal. Also i think it get's in limp mode, because fans turn max speed and computer is slow.

            Even more ;D
            When I disconnect trackpad with keyboard fans also start build up speed, when connected back fan is idling again, so check that.
            Thanks for the reply.
            I see. However, the smc trick did not work for me. In contrast, turning off the laptop holding the shift+power button then turning on the laptop (without connecting the battery) provide the post but it stucks on apple logo. I tried the recovery mode. It connects to the wireless and seems to download the the recovery image but at the end it does not access the recovery menu just stuck on the apple logo as well.

            One more thing i noticed is that VRAM rail provides 1.49v when the laptop is not posting and provides 1.35v when theaptop is posting. So everytime i connect the battery the laptop provides 1.49v at the VRAM power rail. So i strongly beleive there is something to do with that circuit..
            Last edited by Weelcup; 08-26-2020, 07:48 AM.

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              #26
              Re: Apple macbook pro A1398 not posting?

              Got my problem solved by reflashing chip. Program code was partially corrupted. Good luck.

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                #27
                Re: Apple macbook pro A1398 not posting?

                Originally posted by AuroXad View Post
                Got my problem solved by reflashing chip. Program code was partially corrupted. Good luck.
                Really, i am so glad to hear that.
                Have you used any specific bios dump? Did you find it online ?

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                  #28
                  Re: Apple macbook pro A1398 not posting?

                  Originally posted by Weelcup View Post
                  Really, i am so glad to hear that.
                  Have you used any specific bios dump? Did you find it online ?
                  My mac was A1465. Found bios dump on this forum by board number and edited this dump to change serial number, so it matches with the case.

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                    #29
                    Re: Apple macbook pro A1398 not posting?

                    Please can you tell me if u resolve problem with 1398? And how, i have exactly the same problem!

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