4. SERVICE AND ADJUSTMENT
4.1 Frequency synthesizer (PLL)
a) Open the radio, disconnect the antenna and connect apower meter
And a 50 Ohms dummy load with the internal antenna connecting point of
TECtalk.
b) Check the voltage between TP & GND in digital volt meter.
c) Then set the low channel of TECtalk the lowest frequency.
d) After pressed PTT key of TECtalk , trim VC1 for adjusting the lowest
frequency of Tx channel to DC 1.5V in the voltage of TP1.
e) After releasing the PTT key, And then check if the highest frequency
of Rx channel is within DC 1.0V in the voltage of TP,
4.2 TRANSMITTER
a) Connect EUT & measure equipment according to block diagram below.
b) Connect DC 6.0V, voltage preset to EUT.
c) Connect "power meter" & "dummy load (50 Ohms)".
d) Adjust Tx frequency according to trimming trimmer VC2.
e) Connect AF oscillator to mic terminal for conform modulation degree.
f) Adjust the frequency of AF oscillator to 1kHz and adjust AF level
should be 100mV.
g) Checking oscilloscope and modulation meter. max.
frequency deviation should be in +/- 2.5 kHz.
4.3 TRANSMITTER TEST
a) Output Power Test
power(6.0V DC) should be Max.500mW and in -50% range.
POWER SUPPLY
EUT
POWER METER
MODULATION METER
AV VTVM
OSCILLOSCOPE
DUMMY LOAD
DISTORTION METER
AF OSCILLATOR
FREQUENCY COUNTER
SPECTRUM ANALYZER
