Macbook a1707 820-00281 Battery no Power
Hi guys I have a Macbook a1707 with motherboard 820-00281, without liquid damage that behaves strangely, with the battery connected the Macbook does not turn on and the USBC meter stops at 5v in loop, when I disconnect the battery the Macbook turns on and works fine, I have already tried to replace the battery twice without success, as soon as I connect the black cable of the battery the Macbook does not turn on, it stops at 5v and in loop.
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Parts already replaced without success: Battery. U7800. Q7030. Q7040. Q7065. D6950. D6902. U7000. -
Connect the battery and the USB Type C adapter.
Measure the voltage to ground of:
SMBUS_SMC_5_G3_SCL
SMBUS_SMC_5_G3_SDA
at battery connector J6951.Comment
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yes already done, I have no shorts and the voltage goes up to 2.95V and goes in loop, without battery connected I have stable voltage 3.34, I suspect it is the SMC chip.​Comment
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Remove all power. Meter in lowest resistance scale.
Measure the resisance across C7020. We are interested in the full resistance path of the battery leg current sense circuit. What is the resistance in ohms?Comment
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C7020, with black lead to GND and red lead to PIN 1 and then PIN 2, resistance 470 KOHM, while if I put black lead to PIN 2 and red lead to PIN 1, I measure 3.7 OHM, which compared to other working motherboards is too low.​Comment
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Short your meter probes by touching them together. What is the resistance? That is your 0 ohm baseline measurement.
Then when you measure the resistance across pins 1 & 2 of C7020 - the true resistance is the value on the meter - baseline value. There are 3 resistors in the measured path @ R7061, R7060, R7062. We know from the schematics that R7061 = R7062 = 1 ohms each. So your measurement should be ~2 ohms since R7060 = 5 milliohms = 5/1000 ohms.
If you have a working motherboard of the same, measure at the same points of interest. Compare the measurements.Comment
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if I put the tip and the tip has a tolerance of 0.03 ohm, R7061 = R7062 = they are 1 ohm, I don't have an identical motherboard, I take reference from a motherboard of a macbook pro 13.​Comment
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measure the resistance across pins 1 & 2 of C7020 - this should be very close to 2 ohms (not 3R7). Can you confirm this measurement again?Comment
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measures 3.7 ohmComment
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I also replaced the R7060 resistor without success.Comment
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also replaced the resistors R7061 = R7062 and also u7000 once again, without success.Comment
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Remove the battery mosfet off the board and test again with the power adapter and battery attached. Does the power cycling stop and the board boots?
Are the batteries the same as the original and recommended for use in this machine?Comment
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which mosfet should i remove?, the batteries are working on other mocbooks, i noticed that with the battery connected i have no voltage on PPBUS.Comment
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I remove the q7065 mosfet, same defect, 5v in loop on USBC.Comment
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Flux and remove carefully the dual diode @ D6950. Test again.Comment
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removed D6950, nothing usual defect, I'm going crazy!Comment
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Remove all power. Meter in diode mode. Black (yes black) meter probe on PPVBAT_G3H_CONN (because this line is also mating with the ISL9239). Red meter probe to ground. What is the measurement?
How confident do you feel about the soldering of U7000? Perhaps consider to flux it and reflow this part to be sure there are no underside shorts.
The fact that you lose PPBUS_G3H means there is a conflict raised when the battery is connected. SMBUS lines are a common factor and you could be shunting those lines. Maybe both batteries have a defective BMS board but you have mentioned they work in other macbooks? Which battery pack are you testing? What is the part #? 100% confirmed to be compatible with this macbook?
An I2C / SMBUS analyzer would help to reveal the traffic on the SMBUS SDA/SCL lines.Comment
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PPVBAT_G3H_CONN diode mode measures 0.623V, I have already tested two batteries that work on other macbooks, U7000 replaced twice without success, I have an oscilloscope can it help?Comment
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I don't think the PPVBAT_G3H_CONN line is the culprit, because even if I don't put the battery screw but just connect the black battery cable to the J6951 connector without inserting the screw the MacBook doesn't turn on.Comment
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My question pertains to understanding the control circuity inside a Dell PT434 type battery used in Dell E6400, E6410 and other Dell notebooks?
Does anyone have a circuit diagram for the inside of a Dell PT434 battery and/or a description of how the control lines work to control this battery?
My reason for asking is I have a battery which I cannot get to charge beyond 1% in a Dell E6410 or E6400.
The LED bar graph charge indicator on the battery shows one LED lighted when the info button is pressed.
I have tried multiple different Dell power adapters. My Dell... -
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Hi everyone.
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