56
3. Install the remote front housing over the 18 position connector
onto the front of the chassis ensuring that both snaps are
engaged.
4. Place the gasket within the recessed area for the 18-pin
programming connector.
5. Connect the Programming Connector Cover to the main chassis.
VRS Transceiver
Field repair of the transceiver is not recommended. Contact your local
service representative for a replacement transceiver. If replacement of
the transceiver is necessary, refer to the Disassembly & Reassembly
section and the Tuning Procedure section.
VRS Tuning and
Alignment
The VRS is tuned at the factory and should not need to be realigned.
Refer to the proper manuals for programming and alignment for the
associated portable radio and mobile unit before attempting to
troubleshoot the VRS unit. If proper tuning of the associated radio fails
to correct a problem, the following procedure may be used to align the
VRS.
Setup
ASTRO Spectra Station
Cable Setup
Ensure that the ASTRO Spectra B+ cable is disconnected from the
power supply and the control head is off
(WARNING: Never turn B+
power off with the control head still on.)
Connect the VRS DB-25
cable (HKN6153A) into the accessory connector of the mobile.
Connect the other end of the VRS cable to the VRS. Set the test station
power supply to 13.8 Vdc and current limiter to 12 amps. Connect the
mobile’s B+ cable to the power supply (see Figure 31).
Tuning Procedure
Interface Board
Tuning Procedure
1. Place the VRS in the test mode:
a.
Turn off the mobile radio control head.
b. Place the VRS into Test Mode by setting dipswitch S1 pins 1,
2, 3, and 4 to OFF.
c.
Turn on the mobile control head and re-enable the VRS.
d. While in Test Mode, the VRS will not have portable priority
interrupt and will not transmit PL with VRS-to-portable
transmissions.
e.
Figure 32 illustrates the relative placement of the tuning
potentiometers.
2. Adjust the VRS Deviation Level:
a.
Set the Mobile Communications Analyzer RF output to
-50 dBm, with a standard test modulation (1 kHz tone, 3 kHz
deviation).
Summary of Contents for VRS750
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