Second apple MacBook Pro A1706 notebook is not powered on and charged

Second apple MacBook Pro A1706 notebook is not powered on and charged

U3200 is removed, and the failure is still the same. The waveform returned to normal after u3100 was removed. Change two directly. The startup current is completely normal, the fault is eliminated, and the maintenance is over.

Machine model: apple MacBook Pro A1706

Main board version number: 820-00932

Malfunction: The notebook is not powered on and charged.

I received a MacBook Pro A1706 notebook computer, which is a second repair machine. It is not boosted or charged, and a set of CD3215 chips were replaced before.

Second apple MacBook Pro A1706 notebook does not boot and does not charge figure 1

Get the motherboard, first measure the LDO voltage of interface chip CD3215 without short circuit and the voltage is normal.

Second apple MacBook Pro A1706 notebook does not boot and does not charge figure 2

CB304 has no voltage output at this time. According to the time sequence, SMC should get SMC_RESET_L signal, then U1900 clock starts to vibrate, and SMC’s own reading program starts pin configuration. These are all normal. Only the communication between SMC and CD3215 was found to be I2C bus, and one of them was abnormal. I2C_UPC_X_SDA2 can be transmitted normally.

Second apple MacBook Pro A1706 notebook does not boot and does not charge figure 3

I2C _ UPC _ X _ SCL _ 2 is abnormal, and the voltage instantly rises to 3.3V and then falls.

Second apple MacBook Pro A1706 notebook does not boot and does not charge figure 4

There is a resistor R3042 in I2C _ UPC _ x _ SCL _ 2 and EC communication that is disconnected, and then it is found that the EC signal sending end is normal by oscilloscope measurement, and then look at the disconnected waveform.

Second apple MacBook Pro A1706 notebook does not boot and does not charge fig. 5

Test chart of motherboard.

Second apple MacBook Pro A1706 notebook does not boot and does not charge figure 6

The problem is obvious, first remove a 3215 and then test the waveform.

U3200 is removed, and the failure is still the same. The waveform returned to normal after u3100 was removed. Change two directly.

Second apple MacBook Pro A1706 notebook is not powered on and not charged fig. 7

The startup current is completely normal, the fault is eliminated, and the maintenance is over.

Second apple MacBook Pro A1706 notebook does not boot and does not charge fig. 8