Macbook Air 2018 820-01521 no image

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • MicroSMD Lab
    Senior Member
    • Sep 2018
    • 139
    • Trinidad and Tobago

    #1

    Macbook Air 2018 820-01521 no image

    Hi, I need some assistance with this please. Came in with no image, initially I saw nothing on the screen but external display works. Then I saw an image with no backlight on the lcd. While testing the backlight circuit I noticed there was no longer an image on the lcd but the external display still works. Initially I had to disconnect the eDP cable for the external display to work, now the external display will work with or without the eDP cable connected.
    Pin 3 on J8500 reads 12.8 ohms to gnd on diode mode with both + and - on gnd. R8502 is good. No visible corrosion on the board.
    Not sure where to go from here.
  • vvicky8610
    New Member
    • Apr 2017
    • 5
    • greece

    #2
    Re: Macbook Air 2018 820-01521 no image

    check properly if not contact me i try to help you
    Attached Files

    Comment

    • vvicky8610
      New Member
      • Apr 2017
      • 5
      • greece

      #3
      Re: Macbook Air 2018 820-01521 no image

      CPUGT_GLx pins are not connected; so no matters the voltage there.

      Pin 12 should have PWM signal; but ONLY when the chip receives that signal.
      "Pins 12 on U7410 = 0.08 volts, but when I check pin 12 on U7100 this shows 2.4 volts"
      Did you check the continuity?

      As you found corrosion signs on graphics area, this should confirm iGPU damage.
      You can put quality flux and heat CPU; before trashing the board...

      Comment

      • vvicky8610
        New Member
        • Apr 2017
        • 5
        • greece

        #4
        Re: Macbook Air 2018 820-01521 no image

        Disconnect J6100/700 and check again lid signals; their should be 1.8V suposedlly...

        Comment

        Related Topics

        Collapse

        • envym
          MacBook Pro 2018 with Activation Lock
          by envym
          Hi everyone!

          I have a 2018 MacBook Pro (with Sequoia OS) that I've been using for years with no problem. I recently received an M2 MacBook Pro so I'm mostly using it and not the 2018 one, but since a friend of mine needs a computer, I thought I could restore my 2018 and give it brand-new-like to my friend.

          I tried using the built-in tool to restore the MacBook (Settings > General > Transfer or restore > Delete) but it got stuck when trying to remove the Find Device configuration (it asked me for the password for my old Apple ID -now I use the same account but...
          06-27-2025, 08:54 AM
        • Madoy104
          Macbook Pro A1989 - No image, working fine with external monitor
          by Madoy104
          Hi everyone,


          I have a MacBook Pro A1989 that was likely exposed to liquid. It doesn't display an image on the built-in screen, but the screen is backlit (you can't see the Apple logo or any other elements when held up to light). The laptop provides 20V and 1.5-2A, and it works fine when I use it with an external monitor. Currently, the connector for the display (J8500) is disconnected. I'm writing to ask for help in diagnosing the issue. I've heard that when the J8500 is exposed to liquid, the processor pin responsible for the display might short-circuit, and I'd like to know...
          08-15-2024, 10:01 AM
        • robka
          MacBook Pro 2018 - A1990 Dead - not charging - only 5V
          by robka
          Hi,

          my MacBook Pro 15" 2018 Touch Bar (A1990) doesn't charge anymore. Board# 820-01041-A

          I'm not experienced in diagnostics, but I want to try to solve the problem with your help, because every local shop charges around 600€ (650 usd). Which is the value of the whole Macbook.

          The Macbook was charging when suddenly the "charging sound" appeared every other second for around 4-5 times.
          After that the Macbook was dead. It isn't charging anymore.

          The USB-C Port where the charger was plugged is burned. Also The Cable and the...
          03-02-2024, 02:58 PM
        • baglaivlad
          MacBook Pro A2289 (820-01987-A) No boot/image, but boots to DFU
          by baglaivlad
          Hi everyone. Just a reminder I am not a professional repair technician, fixing Apple electronics is my hobby.

          Recently got my hands on MacBook Pro A2289 with interesting behavior. Pristine condition, no water damage, no visual issues whatsoever. It has no image, no CapsLock, no life except the fan is spinning. But it is able to boot into DFU and recognized by another MacBook. I tried to revive and restore the laptop, but the process ends when the MacBook usually should show an Apple logo with a progress bar. I assume the main power lines and T2 are working. It seems like the Intel...
          01-09-2024, 09:55 PM
        • Coguar
          HP ProOne 23.8 inch G9 ALL-in-One Desktop PC - Working when plugged to an external monitor, no image otherwise
          by Coguar
          In the device manager there is no built-in display located. The Intel UHD Graphics are displayed and only the external display is visible. The AiO turns on and works but is only showing a black screen on the monitor.
          I checked the voltage on the backlight connector and it reads ~20V. I tried reseating the LVDS and Backlight connector, yet the image still does not show.

          Does anyone have ideas whether or not this is a BIOS related issue? The only visible log in the BIOS logs is that the firmware was updated around a month ago.
          We already tried to fix it by resetting the...
          06-23-2025, 07:14 AM
        • Loading...
        • No more items.
        Working...