Macbook Pro A2251 Stuck on 5v

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • ronelex
    Senior Member
    • Oct 2016
    • 195
    • Philippines
    #1

    Macbook Pro A2251 Stuck on 5v

    Hi everyone, I have this unit A2251 820-01949.
    I receive this unit with a shorted PP3V3_G3H and found the culprit C8161 shorted and I remove it but the unit still stuck at 5v 0.04A
    This are the readings I got on the unit

    PPBUS_G3H -12.33v
    PP1V8_SLPS2R -0v
    PP3V3_G3H_PMU_VDDMAIN/PP3V3_G3H - 0v
    P1V8G3S_EN from u7800 - 0v

    U3100_W
    PPHV_INT_G3H_W - 5v
    PP1.5_UPC_LDO_CORE_W - 1.5
    PP3V3_UPC_W_LDO - 3.3V
    PP3V3_G3H_RTC - 3.3V

    U3100_R
    PP1.5_UPC_LDO_CORE_R - 1.5
    PP3V3_UPC_R_LDO - 3.3
    PP3V3_G3H_RTC - 3.3

    U3100_X
    PP1.5_UPC_LDO_CORE_X - 1.5
    PP3V3_UPC_X_LDO - 3.3
    PP3V3_G3H_RTC - 3.3

    U3100_T
    PP1.5_UPC_LDO_CORE_T - 1.5
    PP3V3_UPC_T_LDO - 3.3
    PP3V3_G3H_RTC - 3.3​
    Tags: None
    • mon2
      Badcaps Legend
      • Dec 2019
      • 14878
      • Canada
      #2
      Remove all power. Measure the resistance to ground on the power rail that is at 0 volts. Repeat for the enable line for that rail that is also at 0 volts.

        Comment

        • ronelex
          Senior Member
          • Oct 2016
          • 195
          • Philippines
          #3
          PP1V8_SLPS2R -3.7k ohms
          PP3V3_G3H_PMU_VDDMAIN/PP3V3_G3H - 2.4 mega ohms
          P1V8G3S_EN from u7800 - 40k ohms
          I got this low ohms reading on
          L8100 /PP1V1_S3_REG_R - 2.5ohms
          I dont know if this is normal because I dont have any identical board onhand

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 14878
              • Canada
              #4
              Post the diode mode readings of L8100. Remove all power. Meter in diode mode.

              red meter probe, yes red to ground.
              black meter probe to L8100.

              follow this thread - may be the same fault:

              https://boards.rossmanngroup.com/thr...6-0-35a.62664/

              post your updates.

                Comment

                • ronelex
                  Senior Member
                  • Oct 2016
                  • 195
                  • Philippines
                  #5
                  ok thanks for the guide sir, I will update after I check it again

                    Comment

                    Previous template Next

                    Related Topics

                    Collapse
                    • mferna14
                      MacBook Pro A2251 820-01949-A stuck on 5V
                      by mferna14
                      Hi Dear friend., I am working MacBook Pro A2251 Logic board 820-01949-A. The history was that there was slight liquid on the LHS CD3217 & was not powering on at all. No 20v or any amps. I replaced with known good CD3217s & then got the power but its stuck on 5V .18amp. I did power measurements which are below:
                      PPBUS_G3H=12v
                      PP3V3_G3H=3.3v
                      PP3V3_UPC_X_LDO=3.3v
                      PPDCIN_G3H=5v ????
                      PP1V8_SLPS2R=1.8v
                      Do you think the other RHS CD3217 have to be replaced to as they might have gone defective????​
                      11-08-2024, 05:35 PM
                    • MICHAEL_2013
                      Macbook Pro Core I7 A2251 EMC3348 Help Remove MDM
                      by MICHAEL_2013
                      Good afternoon. My client brought me a Mac A2251 EMC 3348 that he bought at a sale. The computer is completely iCloud-free, but it came with MDM installed. He has tried contacting the company that provides the MDM in every way possible, but they are unwilling to offer a solution. The device is:
                      Model A2251 EMC 3348. Serial Number: C02G54CZML85
                      Apple MacBook Pro Core i7 2.3, 13" 2020, 512 GB SSD, 16 GB RAM.
                      I've tried changing the serial number of the SoC ROM MX25U3235F, but it hasn't worked:
                      C02G54CZML84 only works up to Monterey.
                      C02G54CZML86 doesn't work (I...
                      11-20-2025, 11:18 AM
                    • Runnerboys
                      Macbook a2251 Water damage- stuck on Logo
                      by Runnerboys
                      Hi all,

                      Would appreciate your input, we have fixed a water damage motherboard for the a2251, there was mainly corrosion next to the 2 locations, but were able to clean it all

                      First few times- the Macbook would boot and got to login screen (didn't try to login), day after, when we tested it - it would get stuck on the logo and won't show welcome screen

                      What would be the best step to take from here to test? should I test Mobo components/ chip / storage? and if so- where do I start?

                      OR should I try to use the Apple Configurator and connect...
                      05-17-2023, 11:40 PM
                    • Bmet
                      MacBook Pro 13 inch A2238 M2 stuck on 5V
                      by Bmet
                      Hi,

                      I have a MacBook Pro 13 inch A2238 M2 and it was stuck 5V with 0 amps. I measured some important lines and I found a short on PP3V8_AON_MPMU_ISNS_VIN, I tried injecting 1v and I saw heat coming from the mPMU so I removed the pmu thinking that was the problem. I don't know why I didn't check the other side of the border but there it was, a shorted cap. I replaced the cap and the short was gone, so I reballed the PMU and put it on again but voltage was still stuck at 5V and the current was fluctuating between 0 and 0.45 amps. I checked under the thermal camera and I saw the mPM...
                      04-02-2025, 05:02 PM
                    • conghuyms
                      MacBook Air A2179 stuck logo , pls help me !
                      by conghuyms
                      Hey everyone,

                      I’ve got a MacBook Air A2179 that got some water damage through the keyboard. Now it powers on, shows the Apple logo, but just stays stuck there — no startup chime, no keyboard backlight, and no progress bar under the Apple logo.

                      When I try to boot into Internet Recovery (Option + Command + R), the mouse cursor is extremely slow and laggy — like when I lift my finger off the trackpad, the cursor keeps drifting slowly for a second or two.

                      I opened it up and found some corrosion around the LED driver IC area on the logic board. I cleaned...
                      11-05-2025, 08:30 AM
                    • Loading...
                    • No more items.
                    Working...