U8655
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-02-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
41
Troubleshooting USB Connection Failure
USB connection failure
Reinstall the
phone's firmware.
Is the problem
solved?
End
Is the 5-pin mini USB
connector poorly soldered?
Return the phone
to the factory
Re-solder the USB
connector
Y
N
Y
Use a normal USB
cable. Is the problem
solved?
End
Y
N
N
9.4.4 Headset Jack
The headset jack is a 3.5-mm headset jack. When the headset jack has no headset inserted, the
headset jack's pin 3 and pin 4 are open, and the headset detection voltage is at high level.
After a headset is inserted, pin 3 and pin 4 are closed, and the headset detection voltage is at
low level, indicating the insertion of a headset. The HS_DETECT (GPIO86) pin is used to
detect the headset insertion.
The HSED_MICBIAS (PM8029/HSED_BIAS1) supplies power to the headset microphone.
The HSED_HSKEY_ADC (PM8029 MPP5) is used to detect the headset button press.
NOTE
The U8666 supports only LRGM headsets, and does not support LRMG headsets.