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ThinkPadX1 battery is not turned on, but the adapter can be turned on.
“Machine model” ThinkPadx1
【 Fault Phenomenon 】 The battery does not turn on, but the adapter can turn on.
[Maintenance process] I received a machine sent by a customer for repair, the model is ThinkPadX1, and the fault is that the battery does not turn on, but the adapter can turn on. The motherboard number is NM-C661.
ThinkPadX1 battery does not turn on, but the adapter can turn on Figure 1.
There is a problem with the line from the battery to the common point where the charging IC is generated. We directly check the problem of the battery line in the drawing, that is, it is found that the battery seat voltage has not passed through the isolation tube Q34 after being converted into MBAT_PWR18_R, and Q34 is a P tube, so it can only be turned on if G is less than S. To turn on Q34, the control tube Q320 of Q34 should be turned on and grounded. Let R483 and R638 divide the voltage of MBAT_PWR18_R, so that G is less than S, and then Q34 can be turned on. We measure the control signal PWRSHUTDOWN of Q320 and find that it is low level, and this signal needs to be high to turn on Q320. Inquire about the source of PWRSHUTDOWN and find that this signal is sent by U101, so let’s check the working conditions of U101. It is found that the power supply of U101 is supplied by MBAT_PWR18_R through a fuse inductor and diode, and it is found that there is no output voltage after MBAT_PWR18_R passes through the fuse inductor F9, and both ends of F9 are open, so we can directly replace this inductor.
ThinkPadX1 battery is not turned on, but the adapter can be turned on. Figure 2
After testing with battery, it is found that it can be started with battery at this time.
ThinkPadX1 battery is not turned on, and the adapter can be turned on. Figure 3
[Maintenance result] After the machine is installed, the functions of testing sound, network, recording and playing video are all normal, the frame rate of the baking machine is stable for half an hour, and the fault is perfectly repaired. The maintenance is over.
