XIEGU
Product Maintenance Manual G90/G90S Portable Short-Wave Transceiver
XIEGU All Rights Reserved Version No.: 1.0 2022-07 Page
14
of
48
The general parameters of each basic measurement point on the small signal board are as follows:
Maintenance methods:
We are to explain with the default test frequency point of
14.270MHz as an example. The maintenance test frequency point
of each subsequent step is considered to be 14.270MHz by
default.
Measurement
Point
Voltage V
Name
N
0.94
～
0.98
Audio unit reference voltage
Vref
M
3.3
Local oscillator unit power
supply
Q
3.3
Baseband unit power supply
S
3.3
MCU power supply
T
+9
Public 9V power supply
U
+9T
Transmitting 9V power supply
V
+9R
Receiving 9V power supply
W
+5
Public 9V power supply
+9T is only available in the transmitting state, and it is
theoretically 0V when receiving.
+9R is 0V in the transmitting state.
+9, +5, and each 3.3V voltage are available in both the receiving
state and the transmitting state.
Measurement
Point
Frequency
MHz
Amplitude
Vpp
Name
X
12.288
3.9
CODEC clock
P
26.000
3.6
TXCO
reference clock
L
14.270
5.9
Local oscillator
output
R
8.000
1.94
MCU clock
frequency
The local oscillator outputs two signals respectively, and their
frequencies are the same, both of which are the currently set
receiving and transmitting frequencies.
