XIEGU
Product Maintenance Manual G90/G90S Portable Short-Wave Transceiver
XIEGU All Rights Reserved Version No.: 1.0 2022-07 Page
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Fault phenomenon: The hand microphone has no transmitting power
Maintenance methods:
1. Instrument setting:
Name
Setting Parameters
Parameter 1
Parameter 2
Parameter
3
Function signal
source
Frequency: 1
kHz
Amplitude:
250mVpp
/
Oscilloscope
Time base: 1ms
Y-axis:
200mV
X10 gear
2. Connect the test hand microphone to the machine head and measure
the status of the following checkpoints:
Checkpoint
Frequency
Amplitude
mVpp
Name
A36-1
1kHz
200
Audio signal
voltage
A36-2
1kHz
200
Audio signal
voltage
3. Measure whether the two welding points of A36 are connected to the
lower ends of the two inductors of A37 with the on-off gear of
multimeter.
4. Check the welding of the following points:
Fault
Phenomenon
Maintenance Method
Small signal board
Checkpoint
No power at the
hand microphone
Check whether all components
are faultily welded or damaged
A37
5. The measured data at each checkpoint are as follows:
Checkpoint
Voltage V
Name
A39
0.94
Audio reference voltage
Checkpoint
Frequency
Amplitude
mVpp
Name
A38-1
1kHz
200
Audio differential
signal amplitude
A38-2
1kHz
200
Audio differential
signal amplitude
6. Check whether the 16bit-CODEC chip is faultily welded or
damaged.
