U8950 Maintenance Guide V1.0
10 Principles and Failure Analysis
2012-10-22
Huawei Proprietary and Confidential
50
If the U8950 fails to start, locate the fault by checking the startup current when the U8950 is
powered using DC.
1.
No current failure troubleshooting
Connect the phone to the fake
battery and maintenance power
supply, press the power key, and
test the current on the phone.
Is the power-key
copper foil
oxidized?
No current
Clean the key.
Is the clock normal?
Check U201.
N
Y
Y
N
Power-on failure
Check X401
and U3101.
Y
Return the phone to the
manufacturer for repair.
N
Test whether the
VPH_PWR voltage
is normal?
2.
Weak current failure troubleshooting