U8185
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-03-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
23
Excessive current
Excessive current is caused by short circuits. When excessive current occurs, to prevent
damage to components, do not connect the charger to the phone. Power-on failure due to
excessive current is usually the result of short-circuited VBAT circuit.
Check w hether
VPH_PWR and
PM outputs are
short-circuited.
N
Pow er-on failure:
excessive current
Test the VBAT circuit. Is it
a short circuit?
Is J902 normal?
Re-solder or
replace J902.
N
Y
Replace U401.
N
Is Q202 normal?
Remove U201. Do short
circuits still exist?
Y
Replace Q202.
N
Replace U201.
Y
Y
Circuit Diagram Signal Summary
See Table 9-1 in section 9.2.2 "Charging Management Circuits."