U8950 Maintenance Guide V1.0
9 Maintenance Records During Verification
2012-10-22
Huawei Proprietary and Confidential
44
Stage
Station of Fault
Faulty Item
Symptom
Solution
VN1
MMI
MMI01F
The color of the
lower half of the
LCD was slightly
yellow in the
whitescreen test.
LCD defects.
Keep the defective LCD and conduct
further analysis.
VN1
MMI
MMI01F
Incoming defective
LCD
Keep the defective LCD and conduct
further analysis.
VN1
MMI
MMI01F
The signals on
MIPI_DSI_LANE2_
P were abnormal. It
was concluded that
the U401 was
defective.
Keep the board and conduct further
analysis.
VN1
MMI
MMI01E
LCD FPC was
cracked during the
transportation.
Keep the LCD and wait for
confirmation.
VN1
MMI
MMI01E
The boost circuit
failed to generate a
20 V voltage.
The U1303 was
found faulty.
Keep the component and conduct
further analysis.
VN1
MMI
MMI01E
Defective U1303
Replace U1303.
VN1
MMI
MMI01E
D1302 was reversed. Re-solder R1.
VN1
MMI
MMI01D
The grounding pin is
deviated to connect
to the power-on pin.
Replace the grounding pin using the
discard board and test again.
VN1
MMI
MMI01C
The volume down
spring was
deformed.
Adjust the spring position.
VN1
MMI
MMI01C
The phone failed to
access the system
view due to the
software loopholes.
Use the volume up and power key to
drive the phone into forcible upgrade
mode, and restart the phone.
VN1
MMI
MMI01B
The battery support
was poorly soldered.
Re-solder the battery support.
VN1
CT
CT26401N
VBAT is
short-circuited.
After the test, U1002 was found
short-circled. The board process
department was informed to conduct
further analysis.
VN1
CT
CT260013
Thermistor
calibration faulty
Keep the sample and conduct further
analysis.