G700-U10 Smartphone
Maintenance Manual
10 Circuit and Failure Analysis
Issue 1.0 (2013-07-22)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
89
Figure 10-63
FM antenna circuit
Circuit Analysis
The FM function is also provided by the MT6628Q. The FM module uses the I2S interface
for signal transmission. The FM module employs the ground cable of the headset as its
antenna. Therefore, the FM function is disabled when no headset is inserted into the phone.
The FM antenna applies differential signals to improve its anti-interference capability.
Troubleshooting Process
Figure 10-64
Troubleshooting FM failures
FM signal reception
failure
Is the headset jack
properly soldered?
Resolder or replace the
headset jack and check
the surrounding
components
Y
Is the 4-in-1 chip
U2200 properly
soldered?
Resolder U2200
Y
N
N
Resolder or
replace U401