U8655
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
29
End
Y
Power-on failure:
weak current
Reinstall the phone's
firmware. Is the problem
solved?
Is U210's output
voltage normal?
Replace U201
N
N
Replace U401
N
Does X301 have
32.768 kHz output?
Replace U601 and reinstall
the phone's firmware. Is the
problem solved?
Y
Replace X301
N
End
Y
Y
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.