Microsoft Surface pro4 notebook is not powered on for repair

Machine model: Microsoft Surface pro4

Fault phenomenon: notebook no booting

Maintenance process:

The customer sent a Microsoft Surface pro4 for repair, and the customer described the notebook no booting.Connect the power supply source light on, press Switch no response, the first difficulty of this machine is to remove the screen,SMD REWORK STATION 300 degrees, open the strongest wind, quickly move back and forth, everything, about 20 minutes, the screen is completely removed.

Microsoft Surface pro4 notebook is not powered on for repair Figure 1.

notebook no booting

There is no VCC at the common point, is it Short circuit?Test common point to ground value but found no problem, the whole motherboard removed.First fly a wire to connect 12V, so that the current maintenance is more convenient.It seems that the standby current is 0.007 after power on, but the common point is still no VCC.

Microsoft Surface pro4 notebook is not powered on for repair Figure 2.

Plate No

Microsoft Surface pro4 notebook is not powered on for repair Figure3.

Common point to ground diode value:

Microsoft Surface pro4 notebook is not powered on for repair Figure 4.

The main values of Inductor are measured again.

Microsoft Surface pro4 notebook is not powered on for repair Figure 5.

Microsoft Surface pro4 notebook is not powered on for repair Figure 6.

Microsoft Surface pro4 notebook is not powered on for repair Figure7.

Microsoft Surface pro4 notebook is not powered on for repair Figure 8.

Finally, it is found that:

Microsoft Surface pro4 notebook is not powered on for repair Figure 9.

This Inductor normally needs to have 3.3V. After removing the small Inductor, it is confirmed that it is the next level Short circuit, and directly go to Current heating test.Start to adjust 1V VCC burn current is only 0.86a, the motherboard feel completely no sense.So VCC was adjusted to 2V, and the current was 5A instantly. It was a little flustered. I quickly limited the current to 2A. After touching it for a long time, I finally found that it was the problem here.

Microsoft Surface pro4 notebook is not powered on for repair Figure 10.

Small components high temperature, also can not touch which hot.Apply a little bit of Flux directly to it, and adjust the current of Current heating test to 3a.

Microsoft Surface pro4 notebook is not powered on for repair Figure 11.

SMD REWORK STATION removed the Short circuit component and replaced the small Inductor, and the ground value has returned to normal.

Microsoft Surface pro4 notebook is not powered on for repair Figure 12.

The VCC at the common point of power on test has been generated normally, and the standby VCC has also been generated. The switch current runs directly, and the screen booting up is connected.

Microsoft Surface pro4 notebook is not powered on for repair Figure 13.

Microsoft Surface pro4 notebook is not powered on for repair Figure 14.

Microsoft Surface pro4 notebook is not powered on for repair Figure 15.

Some friends in the forum have also sent a map similar to VCC and diode value, but they are not detailed enough, and some of the ground values are greatly different from those measured by my multimeter. I have sorted out a copy with my own fluke 15b +.The sequence diagrams of Inductor HD diode value and VCC are attached (VCC generation sequence is verified by oscilloscope dual channel).