U8185
Maintenance Manual
9 Principles and Failure Analysis
Issue 1.0 (2012-03-23)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
42
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No W2100/1900
transmission
Upgrade the
software. Problem
solved?
End
Is the antenna in
good contact?
Re-install the
antenna
Is U3301 soldered
properly?
Re-solder or replace it
Are L3301, U3302,
L3363, and L3307
soldered properly?
Re-solder or replace
them
Are U3302's power
supply and control
signal normal?
Re-solder or replace
the U3302, replace
C3302, C3301, C3303,
or C3315 on the power
supply network, or
replace C3306, C3307,
or R3312 on the control
circuit
Is U3304 soldered
properly?
Re-solder or replace it
Are L3305, C3316,
and C3314 soldered
properly?
Re-solder or replace
them
Send the phone to an
advanced service site
for repair
Failure: No reception; the phone cannot initiate or receive a call, or access the network.
Solution:
