A1706 Won't Turn on 20V/0.3A draw

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • fharris1977
    Senior Member
    • May 2017
    • 132
    • United States

    #1

    A1706 Won't Turn on 20V/0.3A draw

    I have a MacBook Pro Touchbar A1706 that won't turn on. With the board removed I'm getting 19.62V and an average amp draw of 0.300A. When I first plug in my ampmeter it goes from 5V to 19.62V after a second or 2 and the amp draw starts at about 0.688A and up to about 0.790A and then it gradually goes down to about 0.155A and works it way up to around 0.330A and then it fluctuates in the range of about 0.200A-0.350A. The voltage stays at 19.62V. Can someone with any experience with this issue help me out. I checked all the main power rails and they were present. Anyone know it would be greatly appreciated. Thanks in advance.
  • mon2
    Badcaps Legend
    • Dec 2019
    • 13901
    • Canada

    #2
    What is the voltage to ground of PPBUS_G3H ? Measure @ F7000 (fuse) - check the voltage on both sides to ground.

    Comment

    • fharris1977
      Senior Member
      • May 2017
      • 132
      • United States

      #3
      Hi. The voltage on both sides of F7000 is 13.06V

      Comment

      • mon2
        Badcaps Legend
        • Dec 2019
        • 13901
        • Canada

        #4
        Good voltage. Is it stable?

        Voltage to ground of ALL_SYS_PWRGD ?

        Comment

        • fharris1977
          Senior Member
          • May 2017
          • 132
          • United States

          #5
          Yep its stable. Voltage on ALL_STS _PWRGD is 3.247V

          Comment

          • mon2
            Badcaps Legend
            • Dec 2019
            • 13901
            • Canada

            #6
            This confirms that all power rails are stable and this is the power good signal for each AND'd together = logic '1'.

            Check the SPI flash. Measure the voltage to ground of each pin on the SPI flash (U6100).

            Stable VCC of PP3V3_SUS on this flash device ? Check the voltage of each of the IO pins on this device.

            Comment

            • fharris1977
              Senior Member
              • May 2017
              • 132
              • United States

              #7
              SPI_MLBROM_CS_L=3.354V
              SPI_MLB_IO1_MISO=3.345V
              SPI_MLB_IO2_WP_L=3.344V
              SPI_MLB_IO0_MOSI=0V
              SPI_MLB_CLK=0V
              SPI_MLB_IO3_HOLD_L=3.350V
              PP3V3_SUS=3.357 stable

              Comment

              • mon2
                Badcaps Legend
                • Dec 2019
                • 13901
                • Canada

                #8
                Have you checked the board with a thermal camera? To check for shorted components that may be causing the power cycling event.

                Comment

                • fharris1977
                  Senior Member
                  • May 2017
                  • 132
                  • United States

                  #9
                  No but I did the alcohol test and it evaporated pretty quick off of Q7030. The board was still in the housing though. Its not getting hot outside the board. I feel a little warmth but nothing is burning hot while plugged up outside the housing. I'll check my seek compact pro thermal camera when I find it. Haven't really used it since i bought it.

                  Comment

                  • mon2
                    Badcaps Legend
                    • Dec 2019
                    • 13901
                    • Canada

                    #10
                    With no power -> test the resistance to ground of each coil / inductor to see if there is a partial short. Perhaps the power rails are cycling due to an excessive current draw of at least one rail. You can consider to remove the fuse @ F7000 and see if the power remains on without the cycling.

                    Comment

                    • fharris1977
                      Senior Member
                      • May 2017
                      • 132
                      • United States

                      #11
                      L7430, L7420, L7410 are 3.9ohm. L7210 and L7220 are 7.3ohm. R7220 is 11.3ohm. I don't know if these resistances are supposed to be that low. The other inductors are over 100 ohms or much greater.

                      Comment

                      • mon2
                        Badcaps Legend
                        • Dec 2019
                        • 13901
                        • Canada

                        #12
                        Not at my desk but check the voltage linked to the inductor under test. If it is say 1v0 then yes, it is ok to have a low resistance. Will cross check later and update.

                        Comment

                        Related Topics

                        Collapse

                        • Ryan.man
                          Macbook 2017 with touchbar (A1706) won't turn on after removing the screen
                          by Ryan.man
                          Hello everybody! Posting this in hopes somebody has some expertise that leads to a clear path of troubleshooting that saves me a lot of time!

                          My macbook has the flex cable problem, the one that prevents the screen turning on. Ive been dealing with this for the last 3 years. Last year it went dead and I managed to fix it following youtube tutorials. But my fix wasnt the best, the problem returned a month later. This week, it went dead again. I again tried to fix it.

                          This time the original cable broke too close to the screen, it can't be fixed without tearing the screen...
                          02-04-2025, 12:23 PM
                        • pajdek
                          Lenovo Y700-17ISK turn on and off
                          by pajdek
                          Hello, i have some issues with my laptop Lenovo Y700-17ISK (motherboard BY511 NM-A541), it started when i turn on the laptop, but the lcd wont turn on, i then connected it via hdmi to tv and screen was ok. So i thought maybe lcd stripe is faulty, i removed the bottom cover, disconnected main battery, reset the cmos by disconnecting battery for 1 min, then slighty move the lcd stripe. Conncted power supply and tuned on my laptop, the lcd turn on, it started to load os, then it turn off, after a second it turn on, then after like 3 seconds turn off again, and so on. Removed power supply, waited...
                          09-20-2023, 02:49 AM
                        • RdeveLabs
                          MSI GF63 THIN 11UCX (MS-16R6) LAPTOP WON'T TURN ON AFTER RESTARTING
                          by RdeveLabs
                          To all the members here...

                          Let me tell you a little bit about what happened to my laptop (MSI GF63 THIN 11UCX model: MS-16R6) that “maybe” you know how to solve this problem.

                          So before this problem happened, my laptop was running smoothly. When I wanted to restart my laptop, it looked fine at first. But after I waited for this restart process to take a long time, until finally I panicked (because the restart process did not finish plus the laptop screen only showed a black screen), I immediately pressed and held the power button to force the laptop to turn off. But...
                          05-05-2025, 04:59 AM
                        • robante15
                          Acer Aspire 4520 won't turn on after reboot
                          by robante15
                          Hello, I have an Acer Aspire 4520 from a couple of decades ago and I want to repair it solely for nostalgia.

                          It happens that when I turn it on after having been disconnected for a long time, it turns on without problems, it tells me that the BIOS has been reset and that it will load the factory settings, if I tell it to continue, the computer turns on and everything works fine.

                          The moment I turn it off and want to turn it back on a second time, or restart it and try to start it again, it no longer gives an image, and it no longer responds.

                          If I remove the...
                          04-06-2024, 06:50 PM
                        • masoksian
                          Dell latitude e7470 not turn on .power buton on off and Run Power problem
                          by masoksian
                          Hi everyone,

                          I am dealing with the problem of turning on and off my Dell e7470 notebook.

                          The battery charge light is solid white, I press the button, the power indicator and the light on the button are solid for 1-2 seconds and immediately turn off.

                          The system does not turn on, there is no post.

                          I removed the RAMs and changed them, changed the battery, RTC battery, AC adapter, removed them and waited, tried again, it does not turn on.
                          The problem continues in the same way.
                          I tried to turn on the Fn key, nothing came to the screen....
                          02-15-2025, 12:08 PM
                        • Loading...
                        • No more items.
                        Working...