Macbook Pro A1502 820-4924A BACKLIGHT ISSUE

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • Instafixx
    Badcaps Veteran
    • Jul 2022
    • 374
    • India
    #1

    Macbook Pro A1502 820-4924A BACKLIGHT ISSUE

    Hello,
    i have a Macbook A1502 with No Backlight but the image is on as confirmed by a flashlight.

    the macbook was dirty so i went ahead and cleaned it. the light back on for a couple of minutes and now its again back off.

    The resistance of the Pins at j8300 look okay as confirmed by tallying from a donor board.

    I think its a mosfet issue with the Q7701 but never quite understood how these things work.
    Can anyone guide?
    Tags: None
    • Instafixx
      Badcaps Veteran
      • Jul 2022
      • 374
      • India
      #2
      Re: Macbook Pro A1502 820-4924A BACKLIGHT ISSUE

      Update : Did and SMC Reset, have Backlight for 1 second then it went away !

        Comment

        • Instafixx
          Badcaps Veteran
          • Jul 2022
          • 374
          • India
          #3
          Re: Macbook Pro A1502 820-4924A BACKLIGHT ISSUE

          Originally posted by Instafixx
          Update : Did and SMC Reset, have Backlight for 1 second then it went away !
          Interesting development while checking the LCD Connector Voltages is that when when we touch the meter probe to Point 15 the Lcd starts working normally .

          To confirm I ran a jumper wire from point 15 to point 16 of J8300 and the LCD starts working normally. I think I just bypassed some circuit or mosfet. Would like to do a full proof solution to this so if anyone here can help would be highly obliged.

          Thanks In Advance.

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 14032
              • Canada
              #4
              Re: Macbook Pro A1502 820-4924A BACKLIGHT ISSUE

              Can you post a clear pic of the points on J8300 you have bridged?

              Review the j8300 connector using the boardview file. What are the labels on the pins that you have bridged?

              From the schematic, pin 15 is the negative phase of the data lane 0 for this display. Pin 16 is ground. Need to review exactly which pins you are referencing.

                Comment

                • Instafixx
                  Badcaps Veteran
                  • Jul 2022
                  • 374
                  • India
                  #5
                  Re: Macbook Pro A1502 820-4924A BACKLIGHT ISSUE

                  Originally posted by mon2
                  Can you post a clear pic of the points on J8300 you have bridged?

                  Review the j8300 connector using the boardview file. What are the labels on the pins that you have bridged?

                  From the schematic, pin 15 is the negative phase of the data lane 0 for this display. Pin 16 is ground. Need to review exactly which pins you are referencing.
                  Yes Pin 15 is DP_INT_ML_N<0>.
                  and Pin 16 is Ground.

                  So as i said i was just checking the voltage of the Pins of J8300 with the Macbook on and the battery and display plugged in and when we touch the Pin # 15 the screen comes ON.

                  Even when there is no probe on the ground still the screen used to come ON. Hence making a jumper from 15 to 16 did the trick.

                    Comment

                    • mon2
                      Badcaps Legend
                      • Dec 2019
                      • 14032
                      • Canada
                      #6
                      Re: Macbook Pro A1502 820-4924A BACKLIGHT ISSUE

                      Very strange as this is the data line for the display contents. If you are able to see the expected graphics on the LCD screen, then this data line is working.

                      Perhaps you are allowing for a ground connection and completing the circuit to permit the backlight boosted voltage to be on.

                        Comment

                        Previous template Next

                        Related Topics

                        Collapse
                        • rounin
                          MacBook Air A2337 (820-02016) USB-C Port Issue – Only Works in One Orientation (CC Line Problem?)
                          by rounin
                          Hi everyone,

                          I'm working on a MacBook Air 2020 (A2337, board 820-02016) and running into a strange USB-C issue. I've gone through quite a bit of testing and part replacement, but I'm stuck — hoping someone here can shed some light.

                          🛠 Original Issue
                          The machine initially wouldn't negotiate 20V over USB-C — stuck at 5V.
                          Diagnosis showed PP1V5_UPC0_LDO_CORE shorted to ground.

                          I replaced U3100 (UF400) using a donor board (A2179), and the machine powers on fine now.

                          ⚠️ New Problem: One USB-C Port Only Works in One Orientation...
                          04-19-2025, 01:18 AM
                        • pcbmaniac
                          MacBook A1278 (3115) No PPBUS_G3H Issue
                          by pcbmaniac
                          Subject: Help Needed: MacBook A1278 (3115) No PPBUS_G3H Issue

                          Hello everyone,

                          I'm working on a MacBook A1278 with the 3115 logic board and facing an issue with no PPBUS_G3H voltage. Here's what I've checked so far:
                          1. U7000 Measurements:
                            • Pin 3 has 0V, even though R7012 shows 16.5V from PPDCIN_S5_CHGR.
                          2. Resistors:
                            • I measured R7010 and R7011 with one leg disconnected, and both tested OK.

                          Based on these findings, I believe U7000 needs to be replaced. However, I have a related question:
                          • If I also decide to replace the SMC, do I need to order it pre-programmed,
                          ...
                          12-02-2024, 04:12 PM
                        • sofles
                          Macbook a1707 2017 model 820-00928 GPU issue
                          by sofles
                          Hello there

                          I have problem with Macbook Pro 15" 2017, model 2017, MB code 820-00928.

                          I bought it as broken with some artefacts on the screen, first I thought that this is problem with ribbon cable but after inspectiing ribbon cable I know it is fine. I tried to reinstall macOs and then I figured out that this must be something with GPU as installation freezes at the end (when drivers are loaded). I installed Windows and was able to install every each of drivers except GPU driver, as soon as I tried to install GPU driver - black screen and restart.

                          ...
                          11-21-2024, 05:25 AM
                        • Stephen
                          A2141 MacBook Pro 16" lid sensor issue.
                          by Stephen
                          Just like the title states. I have been confused at this point. Computer won't turn on when lid angle sensor is plugged in, when unplugged it turns on immediately, however I have tried 4 different lid angle sensors all OEM and calibrated without issue. I even pulled one from a donor computer and still nothing. I know the M1 Pro sensors are married to the board however I do know the 2019 intel are not as long as they came from a donor LCD etc. What I do not get is why is the lid angle sensor forcing the computer to not turn on, another issue I see when the lid angle sensor is disconnected...
                          11-01-2024, 03:45 PM
                        • Gueric
                          MacBook Pro 2019 820-01700 Speaker amp issue.
                          by Gueric
                          I have this MacBook Pro on my bench that I have already fixed, hard short on a SSD rail, but it also has another issue. the right speaker sound is either earrape, muffled or absent. Left one works perfect. I have tried replacing it, nothing changed so I'm pretty sure the issue is either motherboard related or maybe software but I doubt that.

                          I don't how to troubleshoot speakers. Any help would be very much appreciated.

                          A refurbisher and a repair shop have already been inside the laptop but I'm pretty sure none of them tried to do any soldering on the board.
                          05-19-2025, 03:08 AM
                        • Loading...
                        • No more items.
                        Working...