Lenovo E15 Gen2 notebook does not charging repair

Machine model: Lenovo E15 Gen2

Plate No.: nm-d011

Fault phenomenon: notebook does not charge

Maintenance process: the measured single battery can be turned on, the adapter can not be charged at the same time, and the single adapter can boost voltage, but no power on, standby 0.015A, take it apart and have a look!

Lenovo E15 Gen2 notebook does not charging repair Figure 1.

Lenovo E15 Gen2 notebook does not charging repair Figure 2.

If there is no drawing, you can only run one line. Refer to the Lenovo nm board repaired before: charging chip 1 pin VCC. The external name of the source should be vssystem2, that is, the common point VCC. Vssystem2 may be converted from 4 pin VBUS of type-C interface through a conversion chip.

VCC e VSPD = 20V bus, the vbpd-20v converter sends out a signal to the vbpd-20v chip, and then the vspd-20v control chip also sends out the control signal to the vbpd-20v chip.

Here the idea is clear, start from the charging chip check.J6 = front lb4708 = front lb4709 = 20V near back tps65994;

Charging chip VCC= near front charging port PL3 = back tps65994ad f6101 = 3.6V;This board does not use conversion chip, but PD directly controls MOS conduction.

Lenovo E15 Gen2 notebook does not charging repair Figure 3.

The conversion MOSFET controlled by tps65994 is not connected. It is suspected that the PD chip or the PD program is broken or the MOSFET problem is suspected. After a simple test of UB4, the selection drop-down is not detected, and the program is not found after searching the forum. It is not sure whether it is the problem here, so start with a simple check.

Qb5, qb6 two N channel MOSFET, qb5 before and after 20V, qb6 is not, ready to measure g level, poke two times, 20V, automatic power on.Because it has not been blown by SMD REWORK STATION, it is unlikely that it is a chip problem. It may be that MOSFET g pole Inveracious Soldering has no high level, resulting in incomplete conduction.Fuse was replaced for the sake of replacement.booting up was OK. It has not been repaired for a week.