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cyber47
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Last Activity: 01-21-2023, 01:12 PM
Joined: 11-13-2018
Location: Cologne
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  • cyber47
    replied to MacBook Pro 820 00923-A seems to boot but no activity
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: MacBook Pro 820 00923-A seems to boot but no activity



    Hello Stevie_belfast,
    sorry for the late reply!

    I don't know if that confirm the CPU is bad, because it could be that the machine does not get into state S0, at least that is my understanding. I am not ready to give up yet, so i will look further into that

    I also checked the rails and mine are also present with steady 1V.

    Have you more information on your machine now?

    Best regards...
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    Leave a comment:

  • cyber47
    replied to Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected



    Hello, thank you for your reply!
    I am sorry for the late reply, i was on vacation over new year.

    I have 20V and after initial changes around 0.8A to 0.9A Current draw, if i have nothing connected to the board (no fans, no keyboard ...). I made a short vid for you to show you my power consumption. You can find the video here: [url]https://youtu.be/gQxMTpfbCIo[/url] (hope this is ok)

    PPBUS_G3H is 13.03V to 13.04V and stable, i have measured PPBUS_G3H for...
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  • cyber47
    replied to Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected



    Thank you very much for your reply! I was on vacation over new year, so sorry for the late reply.

    I don't know the history of the device, i bought it on ebay listed as not turning on. I don't see any signs of flux or other residue and the two liquid indicators i see are white.

    U7100 has a little dust around, i cleaned it but otherwise it looks clean, i have a very low resistant to ground on CPU_VCCSASENSE_P, but i assume that is ok (around 1 Ohm resistance to...
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  • cyber47
    replied to MacBook Pro 820 00923-A seems to boot but no activity
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: MacBook Pro 820 00923-A seems to boot but no activity

    Hello,

    i have currently the same problem ( my thread: [url]https://www.badcaps.net/forum/showthread.php?t=113576[/url] )

    I think the difference between the case from the other forum and ours is, that we have usb activity.

    Does your PPVCC_S0_CPU drops after a short time?

    Does you have PPVCCEDRAM_S0_CPU? That is missing on my board because my CPU does not have CPU_ZVM_L

    I have no solution yet but maybe this can give you a hint Re: MacBook Pro 820 00923-A seems
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  • cyber47
    replied to Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected



    Hello, sorry for the late reply!

    Yes, as far as i know it is the original bios.

    I have no apple logo on external, unfortunately i can only test usb-c to hdmi

    Can you please give me a hint how i check for dfu mode on this model? i only find information about dfu mode for newer macBook Pros.

    Thank you again for your help!

    a little update: i found out, i have stable voltage of 1.046V at the PPVCC_S0_CPU and it is not dropping...
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  • cyber47
    replied to Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected



    Hello,

    thank you for your help!

    I checked PPVCCEDRAM_S0_REG_F at pin 5 of U7760 and i have 1.05V

    I also checked L7700, there i have also 1.05V.

    I followed the Signal and it seems it is missing CPU_ZVM_L at pin 2 of U7790. As far as i know the "_L" means the signal is low in its "normal" state? But i have no second working board to confirm. Do you know if it should be present?

    I checked all voltages...
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  • cyber47
    replied to Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected

    Hello,

    i have a little update:

    1. I tested a charger with 100W but nothing changed.

    2. I am missing PPVCCEDRAM_S0_CPU and after i followed the signal i found out that PPVCCEDRAM_S0_CPU is missing because CPU_ZVM_L is missing.
    But CPU_ZVM_L is generated from the cpu, so i can nothing change here i think.
    I dont know if the signal is necessary or if it should be present at all because in the schematic the signal is negated, if i read it right.

    ...
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  • cyber47
    replied to Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected

    Hello,

    thank you very much for your help

    At first i have news about the board: i checked the connector on the display daughterboard and i have a short on PP5V_S0_ALSCAM_F on the daughterboard. I2C_CAM_SDA is very low resistant to ground on the mainboard and also on the daughterboard.
    I have used capton tape to disconnect the two lines on the connector and the board seems to boot (or behaves like it boots) with the displayconnector in place but i have no PPVOUT_S0_LCDBKLT....
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    Last edited by cyber47; 12-22-2022, 09:21 AM. Reason: typo

    Leave a comment:

  • cyber47
    replied to Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices
    Re: Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected

    Hello,

    sorry for a second post but i have a update:
    The Trackpad seems to work after i cleaned the connector again. I can feel the click now and from what i can see on the amperemeter the Board seems to boot, but i get no display on an external monitor, no chime and no green light on the shift-button. SMC seems to work because if i press the keyboard to perform an smc reset the amperemeter goes to 0A for a short time and up after that.

    If i connect the internal display the...
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  • cyber47
    started a topic Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected
    in Troubleshooting Laptops, Tablets, and Mobile Devices

    Macbook Pro A1706 (820-00923) no boot if display or Trackpad connected

    Hello,

    i have used the search function but i doesnt found my problem.

    I am reparing a MacBook Pro A1706 with the Boardnumber 820-00923-A.

    If i have the display and/or the trackpad installed the Macbook does not boot, i have 20V and 0.03 Amps at the charger (without the battery connected), i can post a video of the Amperemeter if this helps.
    The board has PPBUS_G3H and it seems it is in the S5 state (i have the voltage on the S5 rails but not on the S4 rails).

    If i connect the charger without die display and the trackpad installed...
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  • cyber47
    replied to New Members - please post your introductions here
    in Announcements & Related News
    Re: New Members - please post your introductions here

    Hello,
    i am here to learn, i repair phones, game consoles and Laptops for a hobby but i am very bad at finding the problem, so i am here to learn that and to get help (and hopefully help others) with problems.
    English is not my first language, but i hope everybody can understand what i mean
    Best Regards
    Cyber47
    See more | Go to post

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