Daniels Electronics OSR-3H061, Инструкция по эксплуатации

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IM10-OS3AH
406-470 MHz - Synthesizer Alignment
69
Synthesizer Removal and Installation
Note: Complete synthesizer alignment can
be performed without removing the
synthesizer from the radio.
The synthesizer module is secured to the main
board (MT-3 Receiver IF/Audio Board or MT-3
Transmitter Main board) with a single counter
sunk Phillips machine screw accessible from
the top cover. Remove this screw to remove
the synthesizer module. Using a plastic
coated lifting tool, such as a small screwdriver
with the tip covered in heat shrink material,
gently lift the synthesizer module from the
main circuit board by applying pressure in a
rotating fashion about the four corners of the
synthesizer module. It is important to gently
remove the synthesizer module “straight out”
in order to prevent damage to the connector
pins. Installation of the synthesizer is performed
by fi rst ensuring complete connector pin
alignment; second appling reinsertion force;
and third securing the synthesizer to the main
board with the single countersunk phillips
machine screw. Note the four corner locating
pins on the synthesizer housing assist in
connector pin alignment during the installation.
Circuit Board Removal
Note: Circuit board removal is not required
for tuning purposes.
The analog and digital boards can be removed
using a vacuum de-soldering station. To remove
the analog board: de-solder connections P1,
P2 and P3; remove the SMB connectors J1
and J2 by de-soldering the center pins and
removing the four (2 per connector) M2 machine
screws; remove the seven M2 machine screws
(that secure the analog board) and carefully
remove the analog circuit board. Removal
of the analog circuit board will expose three
inter-board wire connections. Carefully remove
three ferrite beads and six Tefl on washers
from the inter-board connection wires. Attempt
to maintain the position of the three inter-
board wires in order to simplify re-assembly.
The digital board may now be extracted by
removing four M2 machine screws. Follow
a reverse procedure to re-assemble.
Frequency Adjustment and Channel
Selection
Connect a radio communications test set
through a short section of low loss 50Ω coaxial
cable to the synthesizer’s SMB RF output jack
(J2). Select the desired channel code number
via the BCD frequency selection switches on
the main board, or reprogram the synthesizer
memory with a Channel Synthesizer Programer
(CP-SC-3). Turn the power off and back on
and wait a few minutes for the oscillator to
completely stabilize. It should be noted that
the internal synthesizer TCXO, if installed,
operates continuously (regardless of the TX
PTT state) when installed in a transmitter.
The measured RF output signal should be
within ±1.0 ppm of the specifi ed oscillator
frequency at an output level of +5dBm ±2dBm
@ 25°C. Note that an unlocked synthesizer
operation will also be indicated by an unstable or
spurious RF output signal. The “Unlocked” red
LED will be illuminated if the PLL is unlocked.
If a VCO Alignment does not resolve the
unlocked condition, check that the requested
channel code number is within the frequency
range of the particular synthesizer model. An
unlocked condition will probably be rectifi ed
by adjusting the VCO tuning elements as
described in the following procedures.
VCO Alignment
Refer to the ‘Analog Board Component Layout’
diagrams and the ‘Analog Board Schematic
Diagram’ in this section.
Using a high impedance (10 MΩ) DC Voltmeter,
measure the PLL control voltage at TP4 located
on the synthesizer module analog board
(top). Access to TP4 is available through the
synthesizer top cover. The UHF synthesizers
operating in the 406-470MHz frequency range
employ integrated VCO modules having no
external frequency adjustment capability. The
OST-3H418, OST-3H460 and OSR-3H440
models cover frequencies from 406-430MHz,
450-470MHz and 427.4-451.4MHz respectively
and provide full band coverage without tuning
adjustment. For the OST-3H418, measured
PLL control voltages below approximately
+0.5VDC and above approxi4.5VDC
will indicate an “out of lock” condition. For the
OSR-3H440 and the OST-3H460, measured