500 WATT RADIOBEACON TRANSMITTER
ND2000A-02x-xx0
Page 5-18
15 January 2005
(i) Measure and record oscilloscope mod drive
waveform's on/off duty cycle, noting off period
is zero volts and on period is ±15 volts.
(j) The on time recorded in step (i) shall be
between 59 and 65%.
(k) Oscilloscope waveform indication shall be
similar to the waveform depicted in figure 6-11.
(l) Set
RF
switch to
OFF
.
(m) Install connector P6 on A4J1 (A5J1).
(n) Remove shorting clip from resistor A4A2R59
(A5A2R59).
(o) Adjust PWM ramp integrator circuit as detailed
in paragraph 5.3.7.
5.3.18.7 RF Drive-Alarm Check:
Check
RF
DRIVE-ALARM
lamp A4DS2 (A5DS2) function as
follows:
(a) Set or verify switches are set as tabulated for
Test Setting in table 4-1.
(b) Disconnect P6 (P8) from A4J1 (A5J1).
(c) Disconnect P19 (P20) from A4A4J2 (A5A4J2).
(d) Disconnect A4P4 (A5P4) from A4A4J3
(A5A4J3).
(e) Connect output from a variable (0 to 50 volts)
DC power supply between connector A4P4
(A5P4) and ground, ensuring positive lead is
connected to A4P4 (A5P4).
(f) Set output of variable dc power supply to 15.0
V dc.
(g) Set
RF
switch to
ON
.
(h) Reduce output of dc power supply until
RF
DRIVE-ALARM
lamp A4DS2 (A5DS2) just turns
on.
(i) Dc power supply's output voltage shall be
between 9.8 and 10.5 V dc.
(j) Set
RF
switch to
OFF
.
(k) Disconnect dc power supply from A4P4
(A5P4).
(l)
Install A4P4 (A5P4) on A4A4J3 (A5A4J3).
(m) Install P6 (P8) on A4J1 (A5J1).
(n) Install P19 (P20) on A4A4J2 (A5A4J2).
5.3.19
LOW AC POWER CHECK:
The low
AC power check is not performed during functional
test/adjustment procedures. The low AC power check
will be performed in the special adjustment
procedures (refer to paragraph 5.4.3).
5.3.20 LOW BATTERY VOLTAGE
MONITOR:
When applicable, verify transmitter
shuts down when external dc power source voltage
decreases to -42.0 V dc, as follows:
NOTE
The low battery threshold level is set to -42 V dc at the
factory. When the battery voltage falls below this
level, a shutdown-alarm lamp shall turn on and the
transmitter shall turn off. Users have the option of
setting the low battery voltage threshold at a lower
level (see paragraph 5.4.4).
(a) Verify battery panel related links are removed
from between the terminals of TB3-1/TB3-2
and TB3-3/TB3-4 on TB3 (see note on figure
SD-1).
(b) Set switches as tabulated for
Test Setting
in
table 4-1.
(c) Set
POWER-BATTERY
switch A6S2 to
ON
.
(d) Set
RF
switch to
ON
.
(e) Set
MOD
switch A4S2 (A5S2) to
ON
.
(f) Verify transmitter is operating at the intended
carrier level and the intended modulation depth.
(g) Set
POWER-AC LINE
switch A6S1 to
OFF
.
(h)
BATTERY ALARM
lamp shall turn on and a
remote battery alarm control signal (ground)
will be applied to TB3-14.
