Apple A1466 notebook does not start for repair

Carry out mainboard test and maintenance, connect the power supply to test the power supply, and check according to the time sequence; It can be roughly judged that the problem should appear on the bridge side. It is found that the bridge does not emit PM_SLP_SUS_L, and it is abnormal to test 0V at the resistor R8190.

Machine model: Apple A1466 notebook

Main board number: 820-3437-B

Fault phenomenon: the power-on indicator light of the whole machine is not on, there is no response when pressing the power-on key, and the notebook does not turn on.

Maintenance process:

Dismantling bare board test, indicator light does not light up, standby 0.02A does not automatically power on.

Apple A1466 Notebook Maintenance without Booting Figure 1

Observe the motherboard and find that there is water corrosion at the DEBUG interface.

Apple A1466 notebook does not start maintenance Figure 2

Direct hot air gun, removed and cleaned, no corrosion and broken wires were found. When the power supply was turned on again, the indicator light changed from green light to red light, but it was still not powered on to trigger. It seems that it is not so easy to find and leak.

Apple A1466 notebook does not start maintenance Figure 3

Carry out mainboard test and maintenance, connect the power supply to test the power supply, and check according to the time sequence:

1. The common point voltage of PPBUS_G3H is about 8.9V, which is normal.

Apple A1466 notebook does not start maintenance Figure 4

2. The inductor voltage of PP3V42_G3H L7095 is tested at 3.3V, which gives the EC standby voltage.

Apple A1466 notebook does not start maintenance Figure 5

3. Test the EC reset SMC_RESET_L at J6100 port 24, and it is about 3.3V normal.

Apple A1466 notebook does not start maintenance Figure 6

L7560 inductance test, PP3V3_S5 inductance test voltage is 3.3V, which is for the bridge.

Apple A1466 notebook does not start maintenance Figure 7

4. Connect the keyboard cable, press the power-on key SMC_ONOFF_L, and the voltage is 3.3V After short-circuiting the power-on, it is found that EC can normally send out PM _ PWR BTN _ L..

Apple A1466 notebook does not start maintenance Figure 8

5. It can be roughly judged that the problem should appear on the bridge side. It is found that the bridge does not emit PM_SLP_SUS_L, and it is abnormal to test 0V at the resistor R8190.

Apple A1466 notebook does not start maintenance Figure 9

6. The bridge sends out PM_SLP_SUS_L signal only after receiving VCCDSW3_3 and DPWROK. After testing, both VCCDSW3_3 and DPWROK are about 3.3v, and there is no short circuit, and the standby reset clock is normal.

7. If the bridge doesn’t send out PM_SLP_SUS_L, it can’t turn on the PP3V3_SUS voltage behind it, so it can’t be powered on naturally, and the PM_SLP_SUS_L signal goes directly to the bridge, so BGA is the only way out.

8. Fortunately, the current jump of power-on is displayed normally.