HYT TC-618, Service Manual

Page: 74 / 110

TC-618/626 Service Manual
73
CTCSS Deviation (medium), CTCSS Deviation (high) and TX Low Voltage Threshold.
Note: These items are adjusted in the adjustment mode via software.
RX group: VCO Lock Voltage (outside the adjustment mode), Squelch, Rx Bandpass Filter and RX
Low Voltage Threshold.
3. Specific Operations and Requirements
1) The conventional Adjustment Items (outside the adjustment mode) include: TX Frequency
Tolerance, VCO Lock Voltage, Max. Deviation and Modulation Sensitivity.
Note: The profile has programmed CH1, CH2 and CH3 to be wide bandwidth with low, medium and
high frequencies respectively, and CH4, CH5 and CH6 to be narrow bandwidth with low, medium
and high frequencies respectively. Make sure the antenna or load is connected before adjustment.
TC-618/626 VHF
Test Adjustment
Item Condition
Test
Instrument
Test
point
Part Method
Specifications
/ Remarks
Tx Frequency
Tolerance
Rotate the
Channel
Selector
knob
to CH2 and
press PTT to
transmit.
Communication
Test Set
Antenna VR300
Adjust VR300
with ceramic
tuning tool to
control the
center
frequency
within the error
range.
≤ 150Hz
Rotate the
Channel
Selector knob
to CH3 and
press PTT to
transmit.
Adjust TC100
with ceramic
tuning tool until
the lock
voltage meets
the
requirements.
2.8~2.9V
Tx VCO Lock
Voltage
Rotate the
Channel
Selector knob
to CH1 and
press PTT to
transmit.
TC100
Check ≥ 0.8
Rotate the
Channel
Selector knob
to CH3.
Adjust TC101
with ceramic
tuning tool until
the lock
voltage meets
the
requirements.
2.7~2.9V
Rx VCO Lock
Voltage
Rotate the
Channel
Selector
knob
to CH1.
Digital
Voltmeter
CV
TC101
Check ≥ 0.8
Wide
Bandwidth
Rotate the
Channel
Selector knob
to CH1, CH2
and CH3, and
press PTT to
transmit.
Adjust VR200
with ceramic
tuning tool until
the frequency
deviation
meets the
requirements.
3.8~4.5KHz
(4.2KHz is
recommended to
be the maximum
deviation.)
Max.
Deviation
Narrow
Bandwidth
Rotate the
Channel
Selector knob
to CH4, CH5
and CH6, and
Communication
Test Set
BPF:
<20Hz~15kHz
AF: 1kHz
150mV
Antenna
Earpiece
Jack
VR200
Check 1.8~2.3KHz