A1278 no green light

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • Arshad alam4659
    Senior Member
    • Aug 2020
    • 156
    • India
    #1

    A1278 no green light

    I have an A1278 820-3115-B that has no power.
    I don't get green light

    I have 3.4V on PP3V42_G3H
    3.4V on SMC_BC_ACOK_VCC
    2.36 on SMC_BC_ACOK


    U6900:
    2.93 V Sys_onewire
    2.90 Adapter sense
    3.4V SMC_BC_ACOK_VCC
    Any one help
    Tags: None
    • reset1986
      Badcaps Veteran
      • Dec 2014
      • 308
      • italia
      #2
      same problem, the mac doesn't turn on, no light and sys_onwire 2.80v, and adapter sense 2.80 if I remove u6900 it goes up to 3.4v sys onewire and 0.7 V adapter sense It's possible that the u6900 is faulty, I don't have a compatible replacement

      Acok VCC 3.4v
      Thanks

        Comment

        • mon2
          Badcaps Legend
          • Dec 2019
          • 14011
          • Canada
          #3
          Review this thread:

          Macbook pro A1278 820-2936 No light/turn on - Badcaps​

            Comment

            • reset1986
              Badcaps Veteran
              • Dec 2014
              • 308
              • italia
              #4
              Originally posted by mon2
              Review this thread:

              Macbook pro A1278 820-2936 No light/turn on - Badcaps
              thanks it seems my smc is good,
              SMC_BC_ACOK 3.3v
              PPDCIN_G3H 16.4v
              CHGR_ACIN 4v

              SMBUS_SMC_BSA_SCL 3.3v
              SMBUS_SMC_BSA_SDA 3.3v
              SMC_RESET L 3.3v r7000 0 ohm
              PPBUS_G3H 12.2v
              SMC_BC_ACOK_VCC 3.42v
              SYS_ONEWIRE 2.8 v
              ADAPTER_SENSE 2.8v
              if I remove u 6900 SYS_ONEWIRE goes up to 3.4 v ADAPTER_SENSE 0.8v

              suggestions?​

                Comment

                Previous template Next

                Related Topics

                Collapse
                • jheunne
                  a1278 820-2936a fan spin green light only help
                  by jheunne
                  hi there i have a macbook pro a1278 board 820-2936a no boot no dispaly only fan spin and green light. i seen some corroision on top starting to u4900 to u3890 i manage to clean it but still no luck to boot. i figure out that in pp15v t29 there is no available out voltage it shows only 0.6 volts only...
                  10-24-2024, 04:19 AM
                • Arshad alam4659
                  a1278 no green light
                  by Arshad alam4659
                  i have a a1278 820-3115-b with no green light some measure volt
                  PPBUS_G3H=12v
                  PP3V42_G3H=3.43v
                  SMC_BC_ACOK=3v
                  SMC_BC_ACOK_VCC=3.4v
                  SYS_ONEWIRE=3.46v
                  ADAPTER_SENSE=3.42v
                  someone help i try with original charger
                  09-26-2024, 08:21 AM
                • MOSSEP
                  Monitor Audio RSW12 - Green light, but no sound
                  by MOSSEP
                  Hi

                  Im hoping someone might be able to give me some idea of what may be wrong with my Monitor Audio RSW12 Sub.

                  Ive owned it since new in around 2002, so would really like to keep it running if I can, it was the first ‘decent' bit of audio equipment I ever purchased and is a little sentimental.

                  The issue I had was that it would power up with the red light, but sometimes the green light would not come on and I would get no bass from it. If the green light did come on though, I would get sound out of it.

                  I have already tried replacing all of the...
                  01-26-2025, 08:33 AM
                • MOSSEP
                  Monitor Audio RSW12 - Green light but no audio
                  by MOSSEP
                  Hi

                  Im hoping someone might be able to give me some idea of what may be wrong with my Monitor Audio RSW12 Sub.

                  Ive owned it since new in around 2002, so would really like to keep it running if I can, it was the first ‘decent' bit of audio equipment I ever purchased and is a little sentimental.

                  The issue I had was that it would power up with the red light, but sometimes the green light would not come on and I would get no bass from it. If the green light did come on though, I would get sound out of it.

                  I have already tried replacing all of the...
                  01-26-2025, 08:18 AM
                • lcdcaps1
                  820-2610-A Sys onewire help, no green light. Please help from the gurus
                  by lcdcaps1
                  Hi

                  I have an 820-2610-A motherboard that has no green light.
                  I have noticed is when I do a SMC reset the light on the Magsafe blinks.
                  From My understanding, the sys onewire circuit is responsible for the green light on the magsafe
                  The sys onewire circuit on this model and others is more involved
                  I was hoping if anyone knows about this and how it works, can reply and let me know
                  I know this is an old model but I am sure there are people who still works on these or knows about them

                  I get 1.1v on the C7771 capacitor and will replace...
                  11-06-2023, 01:28 PM
                • Loading...
                • No more items.
                Working...