right , i have replaced ud102 , without checking the oscilation on SCL, only SDA , chip was not working on SCL or bad soldering.
i have check second time and see the communication problem.
thanks for you reply. this board got a big liquid damage on keyboard , trackpad connector ,battery was shorted and dead.
now everything is working.
defdjamel
Member
Last Activity: 09-25-2025, 03:29 PM
Joined: 07-12-2025
Location: 13
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I2C_SMC_PWR_1V8_SCL / SDA were stuck at 1.8 V with no oscillation.
I checked I2C_SMC_PWR_SCL / SDA before UD102 → 1.2 V with small oscillation.
I connected the oscilloscope and saw signal activity on I2C_SMC_PWR_SCL, but nothing on I2C_SMC_PWR_1V8_SCL / SDA.
After replacing UD102 driver, now it works correctly and the battery is charging.
another tricky board brought back to life! 💪😎...Leave a comment:
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Thanks for your reply,
On each CD3217:- LDO 3V3 and LDO 1.5 are OK and stable when I plug the USB on the corresponding CD3217.
- diode mode on each LDO -> 0.5 all
- PP3V2_S2 resistance is difficult to measure, it fluctuates between 1 kΩ and 100 kΩ…
Leave a comment:
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5V-0.16A - a2780 -820-02652 - macbook pro m2
Hi ,
on a2780 -820-02652 - macbook pro m2
laptops stuck 5V-0.16A
my measurement :
PPBUS_AON 12V
PP3V8_AON 3.8v
PP3V8_AON_MPMU 3.8
PP1V8_AON 1.8
PP1V2_AON 1.3
PP3V3_AON 1.5 not stable
PP3V2_S2 1.5 not stable
PP3V3_AON resistance to Gnd 60ohms
I injected 3.3 on PP3V3_AON and consumption was 120mA
PMU (U8100) deliver PP3V3_AON ?
If you have an idea..... -
thanks, i clean and its isolated , resitance between the pad is OL .
internal short can damage layer ...
the board is dead.Leave a comment:
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Thanks mon2, UD610 is not present PPBUS_AON and PPBUS_AON_SPKRAMP_ABC are simply shorted in this logic board.. RD698 is a short i will send you a picture.
that will not explain the 3V on PPBUS_AON_SPKRAMP_ABC maybe this line is shorted with other line....
...Leave a comment:
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internal short cut - 820-02935 -A2992 - macbook pro 16" m3 max
820-02935 - a2992 - macbook pro 16" m3 max
Laptop: 5V - 0A
Issue: PPBUS_AON_SPKRAMP_ABC and PPBUS_AON shorted.- On PPBUS_AON_SPKRAMP_ABC, capacitor CR635 was damaged (melted) and created an internal short circuit to ground.
- I removed faulty components (CR635, CR634, CR633) and also chip UR630.
- Result:
- PPBUS_AON_SPKRAMP_ABC → still shorted
- PPBUS_AON → still shorted
When I inject 3 V / 1 A on PPBUS_AON_SPKRAMP_ABC, heating occurs on pad CR635.
I suspect that during the failure, the pad and line PPBUS_AON_SPKRAMP_ABC melted into ground( i try to... -
macbook a1932 no screen , no backlight
hi there , in this A1932 - Air 13 Retina 2018 820-01521, there no screen , no backlight.
no liquid damage.
i have change the lcd flex ,
tested with a working lcd screen but no display , no backlight.
hdmi over usbc is ok .laptop is working .
the same.
here measurement- PP3V3_LCD = 3,3 V
- PP5V_LCD = 5 V
- I2C_SDA_TCON / I2C_SCL_TCON = 3,3 V (no oscilation)
- LCD_PWR_EN = 5 V
- LCDBKLT_EN_L = 12 V
- EDP_BKLT_EN = 0 V
- IPD_LID_OPEN = 1.8 V
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anyone has 820-03160 A2941 board view and schematic ?Leave a comment:
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i make a mistake on my measurement on PPVBAT_AON : 1V with small oscilation to 0.5V.
PPVBAT_AON_CHGR_R = 12V
CHGR_BGATE = 12V
CHGR_BGATE need to be 0V for mosfet Q5265...Leave a comment:
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hi , i already investigate U7440 .
i have changed the component.
here measurement:
PP1V8_AON = 1.8V
PMU_ONOFF_L : 1.8 v and pulse at power ON/OFF
PMU_ONOFF_R_L : 1.8v and pulse during off
CHGR_RST_IN = 0V and no pulse.
PMU_SHDN = 0V and no pulse.
i will resolder u7440Leave a comment:
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Thank you for your answers.
The problem was that I was using a small nozzle (5 mm) on my hot air blower. I replaced it with a 10 mm one, and now it works.
I’ve understood that you don’t really heat the component itself but rather the PCB because of heat dissipation.
Now it’s easy to desolder a CD3217… ✅...Leave a comment:
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And regarding my voltage measurements, is there anything bad?
CHGR_RST_IN 0V is normal ?Leave a comment:
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thanks for your reply , lcd has not been replaced , but logic board is not connected to any screen during the test. charging battery not need screen.Leave a comment:
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A2992 no battery charging
i am completely stuck on this board , who not charging battery(battery tested ok in other logic board).
SMBUS_BATT_SDA, SCL : 1.8V no oscillation. diode 0.5
SYS_DETECT_L = 0V
CHGR_RST_IN 0V
DISP = 0V
ppvbat_AON 12V
pulup resisiatnce SMBUS_BATT_SCL./SDA : 3.3Kohm
I2C_SMC_PWR_SCL /SDA = 1.2V no oscillation ,
UD102 changed
battery connector are ok
i am stuck .
if you have an idea...
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Solder won’t melt on MacBook 2021 logic board – need advice
Hi everyone,
I’m trying to remove a component from a 2021 MacBook logic board, but I’m having trouble.
https://www.electronicsdatasheets.co...s/tlv70733pdqn
I’m using hot air at 480 °C with full airflow and good flux, but the solder paste is not melting.
I know there’s a lot of thermal dissipation from the board, and I suspect the copper planes are absorbing most of the heat.
Do you have any tips for this kind of board? Would a preheater help?
Thanks in advance!
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macbook M3 A2992 820-02918 - No backlight
no backlight on macbook 14" M3 A2992 820-02918,
PPVOUT_LUXE : 12V
BL_PMIC_PWR_EN = 1,2v
the value is normal for 1.2v ?
voltage direct on jumper
is someone already repair this model?
thanks -
macbook pro 16" m2 pro- A2780 - 820-02890 stuck at 5v - 0A
macbook pro 16" m2 pro- A2780 - 820-02890 stuck at 5v - 0A on all usb port and magsafe.
all voltage:
PPBUS_AON = 0V , diode : 0,4
PP3V3_AON = 0V
PPVIN_P3V8AON 0V
PPDCIN_AON_CHGR = 5V
PPVBAT_AON_CHGR_REG = 0V
so U5200 not do the job
on u5200 :
PP5V_CHGR_SW = 4.5 v
CHRG_GATE_Q1 = 0V
1V8_SDA = 0V
1V8_SDC = 0V
i check u5200 diode on PHASE and LX pin -> 0.4
i don't understand something ,
sda and scl in u5200 are pulup by 1V8_S2 ( 0V)
so can not communicate .
1V8_S2 are... -
Hi everybody,
I’m an electronics enthusiast who loves repairing all kinds of devices.
For the past few weeks, I’ve been focusing specifically on Apple laptops.
Looking forward to learning and sharing with the community!...Leave a comment:
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