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Macbook Pro 13" A1278 (Mid 2012) no signs of life

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    #1

    Macbook Pro 13" A1278 (Mid 2012) no signs of life

    Hello everyone,

    I am a novice (or the step just before) trying to troubleshoot a logic board that shows no signs of liquid damage or other abuse, but it will not start. The magsafe charger does not light up at all.

    I know that the charger is OK, and that the magsafe-board is OK.
    I have the board schematics as well as well as a brd layout file.

    I have probed for voltage and it seems my problem starts with the U7090 / LT3470A.
    Here are some probed voltages from that chip and near by;
    Code:
    Pin06 PPCHGR_DCIN_D_R = 0.00v (Probe 1019)
Pin04 P5V5G3H_SW = 0.00v (probe 1090)
Pin02 PP5V5_CHGR_VDDP = 0.00v (probe 1037)

PPDCIN_G3H_INRUSH_FET = 18.5v (probe 1051)

PPCHGR_DCIN_D = 18.63v (probe 212)
PPCHGR_DCIN_D_R = 0.0v (probe 1019)
R7093 = infinite, fail?
R7005 = 20 ohm
C7005 = tested ok
    Could this be the cause of my problems, or am I on the wrong path?

    I have some more probe-points if that would help;
    Code:
    Power rails
PPBUS_G3H = 12.27v (measured on PPBUS_S5_HS_OTHER_ISNS)
PPBUS_S0_LCDBKLT_FUSED = 12.27v (F9700)
PPBUS_S5_FWPWRSW = 12.27v (probe 1345)
PPBUS_S0_VSENSE = 0.00v (probe 1324)
PPVIN_SW_T29BST = 0.0v (measured on Probe 1249)
PPBUS_S5_HS_COMPUTING_ISNS = 12.27v (Probe 877)
PPVIN_S5_HS_OTHER_ISNS = 12.27v (Probe 865)
    BRD file: https://www.dropbox.com/s/d3ejh90yds...115-B.brd?dl=0
    PDF schematics:
    Tags: None
    #2
    Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

    u7000 pin probe

    Comment

      #3
      Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

      Code:
      U7000 / ISL6259HRTZCHGR_ACIN = 4.46v
Pin05 CHGR_ICOMP = 1.13v (probe 175)
Pin01 CHGR_AGATE = 0v (probe 200)
Pin28 CHGR_CSI_P = 18.43 (probe 201)
Pin19 PP5V1_CHGR_VDD = 5.08v (measured on R7001)
Pin20 PP5V1_CHGR_VDDP = 5.07V (probe 202)
Pin03 CHGR_ACIN = 4.46v (probe 176)
Pin02 PPCHGR_DCIN = 18.54v (measured on C7005)
      Anymore pins interesting on the U7000?

      Comment

        #4
        Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

        on white fuse near battery connector you have 12.5 volt ?

        on power on button for smc bypass you dont have 3.42 g3hot volts?


        measure volt in on ld3470 all 6 pins.

        on u7000 u have to check all pins.

        Comment

          #5
          Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

          Originally posted by dellxps15 View Post
          on white fuse near battery connector you have 12.5 volt ?
          18.9v (85W charger)

          Originally posted by dellxps15 View Post
          on power on button for smc bypass you dont have 3.42 g3hot volts?.
          3.46V (probe 882, SMC_ONOFF_L)


          Originally posted by dellxps15 View Post
          measure volt in on ld3470 all 6 pins.
          Do you mean LT3470 / U7090?

          Code:
          U7090 / LT3470A
Pin01 P5V5G3H_FB = 0.00v
Pin02 PP5V5_CHGR_VDDP = 0.00v (probe 1037)
Pin03 P5V5G3H_BOOST = 0.00v
Pin04 P5V5G3H_SW = 0.00v (probe 1090)
Pin06/07/08 PPCHGR_DCIN_D_R = 0.00v (Probe 1019)
          Code:
          U7000 / ISL6259HRTZ
Pin01 = 0v (probe 200) CHGR_AGATE
Pin02 = 18.54v (measured on C7005) PPCHGR_DCIN
Pin03 = 4.46v (probe 176) CHGR_ACIN
Pin05 = 1.13v (probe 175) CHGR_ICOMP
Pin06 = 3.49v (measured on R7012) CHGR_CELL
Pin07 = 0.80v (probe 153) CHGR_VCOMP
Pin08 = 2.05v (measured on R7016) CHGR_VNEG
Pin09 = 0.04v (probe 154) CHGR_AMON
Pin10 = 3.48v (probe 962) SMBUS_SMC_5_G3_SDA
Pin11 = 3.49v (probe 1044) SMBUS_SMC_5_G3_SCL
Pin12 = 3.49v (probe 155) PP3V42_G3H
Pin13 = 3.18v (measured on R7000) CHGR_RST_L
Pin14 = 2.38v (probe 1018) SMC_BC_ACOK
Pin15 = 0.07v (probe 157) CHGR_BMON
Pin16 = 11.45v (probe 156) CHGR_BGATE
Pin17 = 12.27v (C7050) CHGR_CSO_N
Pin18 = 12.28v (C7050) CHGR_CSO_P 
Pin19 = 5.08v (measured on R7001) PP5V1_CHGR_VDD
Pin20 = 5.07V (probe 202) PP5V1_CHGR_VDDP
Pin21 = 0.18v (probe 1036) CHGR_LGATE
Pin22 = GND
Pin23 = 11.84v (probe 1045) CHGR_PHASE
Pin24 = 11.92 (probe 1034) CHGR_UGATE
Pin25 = 16.01v (probe 214) CHGR_BOOT
Pin26 = 16.30v (probe 1050) CHGR_SGATE 
Pin27 = 18.43 (C2070 ) CHGR_CSI_N
Pin28 CHGR_CSI_P = 18.43 (probe 201) CHGR_CSI_P
          Btw; in all measures battery is not connected, only fan and magsafeboard+charger.
          Last edited by pearman; 10-10-2014, 03:10 PM. Reason: Added info about battery connected

          Comment

            #6
            Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

            ok, check voltage on F7040

            then check voltage on U6990

            Comment

              #7
              Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

              Originally posted by dellxps15 View Post
              ok, check voltage on F7040
              Code:
              F7040 = 12.27v both sides (PPBUS_G3H probe 1345, PPVBAT_G3H_CHGR_REG probe 211)
              Originally posted by dellxps15 View Post
              then check voltage on U6990
              Code:
              U6990 / PM6640
Pin01 = NC
Pin02 = 3.82v (probe 1131) P3V42G3H_FB
Pin03 = 9.37v (probe 328) P3V42G3H_TON
Pin04 = 18.60v (probe 220) PPVIN_G3H_P3V42G3H
Pin05 = GND
Pin06 = 3.47v (probe 219) P3V42G3H_SW
Pin07 = 18.60v (probe 220) PPVIN_G3H_P3V42G3H
Pin08 = 3.82v (probe 1131) P3V42G3H_FB
Pin09 = 3.49v (probe 155) PP3V42_G3H
Pin10 = 3.30v (probe 323) P3V42G3H_REF3
              It seems like after a few minutes, voltage disappeared on PP3V42_G3H_REG. Restored by re-connecting magsafe..

              Comment

                #8
                Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                all voltage seems ok, but you said that no green light on magsafe?

                Comment

                  #9
                  Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                  Originally posted by dellxps15 View Post
                  all voltage seems ok, but you said that no green light on magsafe?
                  Yep, magsafe light is off. Should U7200 be off? (no enable on pin13)
                  It seems that way if I read page 73 correctly..

                  Code:
                  U7200 / TPS51125
Pin01 = 0.0v (probe 890) P5VS3_ENTRIP
Pin02 = 0.0v (measured on R7267) P5VS3_VFB
Pin03 = 0.0v (probe 874) P5VP3V3_VREF
Pin04 = 0.0v (probe 881) P5VP3V3_REG3
Pin05 = 0.01v (measured on R7269) P3V3S5_VFB 
Pin06 = 0.0v (probe 889) P3V3S5_ENTRIP
Pin07 = 0.01v (pin7) P3V3S5_VO2
Pin08 = 0.0v (probe 881) P5VP3V3_REG3
Pin09 = 0.0v (probe 880) P3V3S5_VBST
Pin10 = 0.01v (probe 906) P3V3S5_DRVH
Pin11 = 0.01v (probe 923) P3V3S5_LL
Pin12 = 0.0v (probe 873) P3V3ST_DRVL
Pin13 = 0.3v (measured on R7273) 5V3V3_REG_EN
Pin14 = 0.0v (probe 874) P5VP3V3_VREF
Pin15 = GND
Pin16 = 12.28v(probe 865) PPBUS_S5_HS_OTHER_ISNS
Pin17 = 0.0v (probe 866) PP5V_S5
Pin18 = NC
Pin19 = 0.0v (probe 1433) P5VS3_DRVL
Pin20 = 0.0v (probe 875) P5VS3_LL
Pin21 = 0.0v (measured on Q7260/4) P5VS3_DRVH
Pin22 = 0.0v (measured on R7260) P5VS3_VBST
Pin23 = 0.0v (probe 430) P5V3V3_PGOOD
Pin24 = 0.0v (probe 891) P5VS3_VO1

                  Comment

                    #10
                    Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                    check q7221, q7220,

                    but because magsafe green light is off, something must be bad in power circuit.

                    Comment

                      #11
                      Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                      Originally posted by dellxps15 View Post
                      check q7221
                      Code:
                      Q7221 / SSM6N37FEAPE
Pin01 GND
Pin02 3.27v (probe 1520) P5VS3_EN_L
Pin03 0.0v (probe 889) P3VS5_ENTRIP 
Pin04 GND
Pin05 3.32v (probe 904) P3V3S5_EN_L
Pin06 0.0v (probe 890) P5VS3_ENTRIP
                      Originally posted by dellxps15 View Post
                      check q7220.
                      Code:
                      Q7220 / RJK0216DPA
Pin01 0.0v
Pin02 GND
Pin03 GND
Pin04 GND
Pin05 0.01
Pin06 12.28
Pin07 12.28
Pin08 12.28

Leftside,
L1 0.01
L2 0.01
L3 12.28v

Rightside,
R1 0.01
R2 0.01
R3 12.28v
                      The BRD doesnt match pinout for this one?

                      Comment

                        #12
                        Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                        check u7200 if some pin is shorted

                        edit: look q7220 dot for pin 1 start.... pin 5 should be 1 going on side by side.

                        edit: on that page, one dude have the exact same issue as you.

                        http://forums.macrumors.com/showthread.php?t=1628993

                        post number 12.
                        Last edited by dellxps15; 10-12-2014, 01:20 PM.

                        Comment

                          #13
                          Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                          U7200:

                          Nothing shorted to GND at least, except Pin15.

                          Interesting post there. I checked the area around U5010 and there is some residue visible with microscope.

                          I wasnt made aware the board had liquid damage but this sure looks like it, so I'm going to give it a good cleaning.

                          U5010-area:

                          (I missed this checking with magnifier..)

                          Comment

                            #14
                            Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                            check also u7941 volts.

                            Comment

                              #15
                              Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                              Originally posted by dellxps15 View Post
                              check also u7941 volts.
                              Code:
                              U7941 / SLG4AP012
Pin01 3.49v (probe 155) PP3V42_G3H
Pin02 0.0v (probe 1233) SMC_PM_G2_EN 
Pin03 0.0v (probe 872) P5V3V3_REG_EN
Pin04 3.32v (probe 324) P3V3S5_EN_L_R
Pin05 GND
Pin06 0.01v (probe 1480) PP3V3_S5
Pin07 0.0v (probe 1189) S5PGOOD_DLY
Pin08 0.0v (probe 327) S5_PWRGD

                              Comment

                                #16
                                Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                                Ok so I checked
                                Code:
                                U5010 / SN0903048
Pin01 3.49v PPV3V42_G3H
Pin02 GND  
Pin03 3.49v PP3V42_G3H
Pin04 1.0v SMC_MANUAL_RST_L
Pin05 3.18v SMC_RESET_L
Pin06 3.33v SMC_TPAD_RST_L
Pin07 3.46v SMC_ONOFF_L
Pin08 3.30v PP3V3_S5_AVREF_SMC
                                And it seems to generate SMC_RESET_L correctly, to SMC U4900?
                                But from U4900 there is no SMC_PM_G2_EN, which is why it doesnt power on?

                                Measured from U4900 and it's giving power on:
                                PP3V3_S5_AVREF_SMC 3.30v
                                PP1V2_S5_SMC_VDDC 1.21v
                                PP3V3_S5_SMC_VDDA 3.49v

                                Code:
                                Q5490
Pin01 0.0v
Pin02 0.0v
Pin03 0.0v
Pin04 18.95
Pin05 17.2
Pin06 15.7

                                Comment

                                  #17
                                  Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                                  with multimeter in diode mode, or for check short, look if you have some short at some coil.


                                  im still learning macbook power sequence , problem looks like on u7200 and 3.3volt enable, but that no green light on magsafe is a bad thing. try also disconnect bil cable (battery indicator cable)

                                  Comment

                                    #18
                                    Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                                    Originally posted by dellxps15 View Post
                                    with multimeter in diode mode, or for check short, look if you have some short at some coil.


                                    im still learning macbook power sequence , problem looks like on u7200 and 3.3volt enable, but that no green light on magsafe is a bad thing. try also disconnect bil cable (battery indicator cable)
                                    If you check here;


                                    It seems like the signal P5V3V3_REG_EN is from signal SMC_PM_G2_EN (which is 0). P3V3S5_EN_L_R is inverted SMC_PM_G2_EN, and voltage here is good, so I think U7200 is good, but simply not getting the right signals from U7941?

                                    U7200 enable (P5V3V3_REG_EN) comes directly from SMC_PM_G2_EN

                                    Bil-flex/board is disconnected. Only charger/fan connected.
                                    Last edited by pearman; 10-14-2014, 01:01 AM.

                                    Comment

                                      #19
                                      Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                                      5v is on after pressing power botton, so p5v3.3 should be ok when 0v.

                                      problem is no 3.3 volt on u7200 and on pin 4 of u7941 u have 3.3 volt... but no in pin 3 and no 1.3volt on pin 8.

                                      no short on u7941 pins (except pins 5 and 9) ?

                                      if no greenlight means smc is not happy with some voltage, and that s5pgood should be ok and not 0v.

                                      Comment

                                        #20
                                        Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

                                        No shorts on U7941, except GND then

                                        What about previous chip U7090, does it not seem suspicious that R7093 is infinite?
                                        Picture of R7093 pads?
                                        Last edited by pearman; 10-14-2014, 04:41 PM.

                                        Comment

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