Huawei U8655N Maintenance Manual page 36

U8655
Maintenance Manual
GSM_PA_EN
H
L
GSM_PA_BAND
L
H


Before starting the following process, make sure that the USIM card and the antenna are well
connected.
Issue 1.0 (2012-02-23)
GSM/DCS transmission
f ailure
When the RF cable is not
inserted, are U3201's pin
1 and pin 2 connected?
Y
Are U3202's control signals
normal?
Y
Are U3501's GSM output
and DCS output
approximately 33 dBm and
30 dBm respectively?
Y
Do U3801's pin A10 and pin
Y
A9 have output?
Y
Check U401
NOTE
 The following tables describe the working status of the GSM/DCS power amplifier U3501.
H: voltage higher than 1.3 V. L: voltage lower than 0.5 V.
WCDMA transmission failure (use W2100 as an example)
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Copyright © Huawei Technologies Co., Ltd.
9 Principles and Failure Analysis
N
Check U3201
N
Check U3202 and
U401
N
Check U3501
N
Check U3801
PA
ON
OFF
MODE
GSM850/900
DCS1800/1900
31