Huawei U8185 Maintenance Manual page 43

U8185
Maintenance Manual
Issue 1.0 (2012-03-23)
No GSM
transmission
Upgrade the
software. Problem
solved?
N N
Is the antenna in
good contact?
Y Y
Are C3906 and
C3909 soldered
properly?
Y Y
Are R3502 to R3507
soldered properly?
Y Y
Are L3500, L3504,
and C3510 soldered
properly?
Y Y
Are L3501, C3514,
and C3513 soldered
properly?
Y Y
Is U3501 soldered
properly?
Y Y
Are U3501's power
supply and control
voltage normal?
Y Y
Send the phone to an
advanced service site
for repair
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Copyright © Huawei Technologies Co., Ltd.
Y Y
End
Re-install the
N N
antenna
Re-solder or replace
N N
them
Re-solder or replace
N N
them
Re-solder or replace
N N
them
Re-solder or replace
N N
them
Re-solder or replace it
N N
Re-solder or replace
the U3501, replace
C3521, C3503, C3522,
N N
C3501, or C3502 on the
power supply network,
or replace C3518 or
C3519 on the control
circuit
9 Principles and Failure Analysis
38