Huawei U8860 Maintenance Manual page 48

U8860
Maintenance Manual
Note: Check the control signals of U3202 switch using a multimeter or oscilloscope. The truth
table for control signals is as follows:
Note table 1:
TRX_W2100
TRX_W900
GSM900 Rx
GSM1800 Rx
In W900, just replace the U3404 detection with U3804 detection.
In GSM, just replace the U3404 detection with U3304 detection.
Issue 1.0 (2011-11-14)
The reception channel in
W2100 is faulty.
Are U3201 Pin 11 and Pin 8
connected when the RF
cable is not connecting?
Y
Is U3202's switch control
signal normal? (The truth
table is the note table 1.)
Y
Are the signals of U3404 Pin 1
and Pin 8 normal (the
difference is less than 2.3 db) ?
Y
Is U4001's IQ signal normal?
Is the power voltage normal?
Y
Check U201.
VC1
1
1
1
0
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9 Principles and Troubleshooting
N
Check U3201.
N
Check U3201 and
U201.
N
Check U3404.
N
Check U4001.
VC2 VC3
0 1
1 1
0 0
0 1
VC4
0
0
0
0
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