Vector-LP Radio Beacon Transmitter Technical Instruction Manual
Page
4-3
Section 4 Testing and Adjustment
Issue 1.1
4.3.1.3
Some of the transmitter’s PWBs
may be duplicated and connected as active
(main) and reserve (standby). The front
panel diagnostic display provides selection
of the active side (A or B). The following list
identifies the duplicated PWBs/assemblies
and which are active for a specific
selection. Refer to Figure 4-1 to locate
these assemblies. To locate an assembly’s
adjustment or test point, refer to the
controls and indicators portion of Section 3.
Side A Assemblies
RF Synthesizer PWB .......................................A5
Interphase PDM Driver PWB...........................A6
Exciter Monitor/Generator PWB ......................A7
RF Power Module ..........................................A12
LVPS Module ...................................................U2
Side B Assemblies (optional)
RF Synthesizer PWB .......................................A8
Interphase PDM Driver PWB...........................A9
Exciter Monitor/Generator PWB ....................A10
RF Power Module ..........................................A13
LVPS Module ...................................................U3
4.3.2 Test Equipment Required
A dummy load rated for twice the
maximum power capability of the
transmitter, an oscilloscope and a digital
multimeter are required to perform the
functional test procedures. Refer to Table
1-2 for recommended test equipment.
4.3.3 Test Prerequisites
The following steps must be completed
prior to performing any of the functional
test procedures:
(a) Verify that nothing affecting the RF
power stage has been changed or
altered since the initial start-up
procedure (described in Section 2 of
this manual) was completed.
(b) Ensure the ac or dc power source is
turned off or disconnected.
(c) Terminate the transmitter's RF output
into a suitably rated, precision 50
:
,
load that is able to accurately display
the RF power being applied to it.
WARNING
If there is a jumper between TB1-19 and
TB1-20 on the remote interface PWB,
safety features provided by the external
interlocks are disabled. Implement a
fail-safe method to alert personnel to
this fact. Dangerous voltages will be
present near the RF output and the
antenna system if the transmitter is
turned on under these conditions.
(d) Close all external interlocks or connect
a jumper between TB1-19 and TB1-20
of the remote interface PWB.
NOTE
Remote interface PWB A3 is located on the
back of the front panel.
NOTE
This section makes frequent reference to
Section 3 - Operating Instructions. You
should be familiar with the transmitter’s
operating instructions, specifically the front
panel GUI, before testing or adjusting the
transmitter’s circuits.
4.3.4 Initial Turn-On
Enable the ac or dc power source, turn on
the transmitter, and observe its alarm and
status indicators as follows:
(a) Verify the requirements of paragraph
4.3.3 have been completed.
(b) Turn on (enable) the ac or dc power for
the transmitter. The
AC IND
lamp on
each RF power module (viewed from
transmitter top) will be on. The
presence and value of ac voltage can
also be viewed on the front panel GUI.
Ensure the transmitter’s RF power
stage is disabled by pressing the
Control - RF OFF
switch.
(c) Select local control by pressing the
Control - Local
switch.
