It is not a common fault that Lenovo Y7000 notebook can not be powered by CPU when it is not turned on

After checking the drawings and measuring, it was found that the south bridge was damaged, and the return signal from the south bridge to the CPU was not processed, which led to the failure of the CPU power supply. The south bridge was replaced, and the power supply came out. Installation, startup test, perfect lighting, troubleshooting, and maintenance are over.

Machine model: Lenovo Y7000 notebook

Main board version number: FY510 NM-B961 Rev:1.0

Malfunction: The notebook does not boot.

Maintenance process:

A Lenovo Y7000 notebook, this machine is the second repair machine, the fault is that the notebook doesn’t start and the CPU doesn’t supply power, which is a common fault of this model, mostly caused by the abnormal 47-pin resistor of the power supply chip MP2949, and the fault of replacing 2M resistor is the same. The VCCSA power supply has come out, and the current is 0.6. Except VCCCPUCORE and VCCGFXCORE, other power supplies are normal. The power supply chip MP2949 fails.

Check that the conditions PCH_PWROK, SYS_PWROK, H_CPUPWRGD and CPU_PLTRST# are all normal. Basically, all the conditions required for CPU power supply are met, except that the power supply is not available.

Check where the motherboard has been repaired. The CPU model of this machine is I7-8750H. Replace the i5-8300H CPU, and the CPU failure is the same.

Second, Lenovo Y7000 notebook can’t be powered by CPU if it’s not turned on. figure 1

There is still no CPU power supply. The startup of this machine chip is given by EC. When the EC is damaged, there is no CPU power supply. The EC is replaced, but the CPU still fails to supply power.