U9500 Maintenance Guide
9 Troubleshooting
Issue 1.2 (2012-6-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
44
Figure 9-7
Handling process for the excessive current power-on failure
9.2.3 Weak Current
Cause
Low current is usually caused by the system starting improperly or the PM chip being
partially short-circuited or damaged. This failure may be due to a faulty main chip or memory
chip. The low current ranges from 20 mA to several hundred mA.
Figure 9-8 shows the components, damage on which can cause the weak current power-on
failure.
N
Resolder or
replace
correspondin
g
components.
Check whether the
VPH_PWR is
short-circuited.
End
After the phone is connected to a USB
charger or fake battery, and the Power
key is pressed, a large current is
detected.
Is the VBAT
short-circuited?
Are the elements of the
battery connector
short-circuited?
Y
Y
Check whether U1901, U1301,
U4801, and U4704 are
short-circuited.
N
Resolder or
replace
corresponding
components.
Y
Are other components, especially
those close to the connector, are
short-circuited?
N
Is the current
recovered after
U1901 is
soldered?
N
Y
