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| MacBook A1706 (820-00923) No S5 volltages on A1706 https://vlab.su/viewtopic.php?f=51&t=116926 |
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| abuholm [ 03 июл 2021, 05:50 ] | |
| Заголовок сообщения: | MacBook A1706 (820-00923) No S5 volltages on A1706 |
Hello everybody, this MacBook suffered liquid damage around the battery (area with chip soldered) and right under the SMC chip (U5000) and around J4500. After washing and drying, R3041, R3042,L5001 were replaced .5v appears with a current draw of 0.03A when power is connected (without battery) to any of the 4 ports, and also I noticed that there is oscilloscope activity on R3042 (I2C_UPC_X_SCL2) (3v) but not on R3041 (I2C_UPC_X_SDA2) ( voltage pulled down to 1.12v). A diode-mode check to ground revealed that R3042 (connected to U3100 and U3200) had a reading in excess of 2000, whilst R3041 ( also connected to U3100 and U3200)had a reading of a little over 700. After disconnecting R3041, voltage rises to 3v and oscilloscope shows activity. There are no short circuits on the coils. Now, when power is connected to the motherboard + battery (battery is charged), voltage rises from 5v to 20v (with 0 current draw) on any of the 4 ports. There are no voltages on the motherboard with the exception of L6900 (PP3V3_G3H_REG_R) which I suppose powers the SMC. When 3.3v is applied to SMC_PM_G2_EN, 3.3v appears on L7660 (PP3V3_S5) which suggests that U7650 is functional. I somehow suspect either U3100 or U3200 is faulty because of the 2C_UPC_X_SDA2 voltage draw down issue, but then 20v rises when power is connected to those 2 chips as well. Is there a way to disable them?. I need help on what is needed for the SMC to start. PS: what's the safest way to remove the epoxy around the CD3215A chips? |
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