Figure 9-27 Troubleshooting Process For Receiving Failure - Huawei U8815 Maintenance Manual

U8815
Maintenance Manual

Figure 9-27 Troubleshooting process for receiving failure

Table 9-6 describes truths for control signals.
Issue 1.0 (2012-02-13)
Failure of the W2100
receiving channel
Check U3201 when the
handset is not connected
to the RF cable.
Are pins 1 and 2 of U3201 connected?
Y
Check
whether the control signal of the
U3202 switch is normal (For the
truth table for control signals,
see Table 1.)
Y
Check
whether signals on pins
1 and 8 of U3401 are normal and the
maximum insertion loss is smaller
than or equal to 2.3 dB.
Y
Check
whether the IQ signal of U3901
and the power supply voltage
are normal.
Y
Check U401.
Y
End
NOTE
Check the control signals of U3202 switch using a multimeter or an oscilloscope. The truth table for
control signals is as follows:
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9 Principles and Failure Analysis
N
Check U3201.
N
Check U3202 and U401.
N
Check U3404.
N
Check U3901.
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