U8655
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
29
N
N
Test the VBAT circuit.Is it
a short circuit
Y
Y
N
N
N
N
Y
Y
Powe-on failure:
excessive current
Check whether
VPH_PWR and
PM output are
short-circuited
Is J902 normal?
Y
Y
Is Q201 normal?
Remove U201.Do short
circuits still exist?
Y
Y
Replace U401
N
N
Re-solder or
replace J902
Replacec Q201
Replace U201
9.2.2 Charging Management Circuits