RADIOBEACON TRANSMITTER
ND500II (125 WATTS) DOUBLE SIDEBAND - NO VOICE
Page 5-15
15 September 2003
(g)
Verify a ground is present on A11TB1-19,
'
REMOTE BATTERY STATUS
' output.
(h)
Verify transmitter has resumed normal
operation while being supplied from the DC
power source.
(i)
Turn on AC power at service entrance.
(j)
BATTERY-ALARM
lamp DS9 shall turn off.
(k)
Transmitter will automatically switch to the AC
power source and resume normal operation.
(l)
AC POWER
lamp DS10 shall turn on.
(m) Verify ground is removed from A11TB1-19,
'
REMOTE BATTERY STATUS
'
output.
SPECIAL CALIBRATION PROCEDURES
5.4
Procedures referred to as special
calibration procedures require test equipment not
normally available at transmitter sites or disassembly
of assemblies and removal of wiring within the
transmitter in order to calibrate their respective
circuits. The adjustments have been pre-set at the
factory prior to shipment and should not require
further adjustment. The accuracy of the settings will
affect accuracy of functional tests/calibration
procedure settings. Therefore, they should not be
disturbed unless their accuracy is suspect and then
only if the specified test equipment is available.
5.4.1
TEST METER M1'S DC CURRENT
INDICATION CALIBRATION
: Calibrate the
accuracy of
TEST
meter M1's lower scale 'Amps'
indication when
DC CURRENT
is selected by
TEST
meter S6, as follows:
NOTE
Calibration of
TEST
meter M1's DC current
indication should not be required unless a circuit
component is damaged and/or replaced. If a repair
has been affected or the meter reading is suspect,
the following procedure will restore the 'Amps'
indication on
TEST
meter M1 to the required
accuracy.
(a)
Verify the requirements of paragraphs 5.3.2
through 5.3.13 have been completed.
(b)
Set
O/P PWR
potentiometer A4R31, on
modulator driver PWB, fully counter
clockwise.
(c)
Set switches, except
POWER
switch S3, to
positions tabulated in table 4-1 for
Calibration
Setting
. Set
POWER
switch S3 to
OFF
.
(d)
Disconnect wire #20 from terminal 2 of
inductor A1L1 (refer to figure MD-4 to locate
power supply A1 and to figure MD-6 to locate
inductor A1L1.
(e)
Connect a 10-amp DC ammeter in series with
output of inductor A1L1. Connect ammeter's
positive input to A1L1-2 and negative input to
lug of wire #20, removed in step (d).
(f)
Set
TEST
switch S6 to
DC CURRENT
.
(g)
Set
POWER
switch S3 to
ON
.
Do not permit RF output to exceed 125 watts.
(h)
Simultaneously monitor dummy load's power
indicator and DC ammeter indication and then
adjust
O/P PWR
potentiometer A4R31 for a DC
ammeter indication of precisely 3.0 amperes.
(i)
Adjust
CURRENT CAL
potentiometer A8R5 for
an indication of precisely 30 (3.0) 'Amps' on
TEST
meter M1's lower scale.
(j)
Set
POWER
switch S3 to
OFF
.
(k)
Disconnect DC ammeter from inductor A1L1-2
and wire #20.
(l)
Connect wire #20 to terminal 2 of inductor
A1L1.
(m) Set
POWER
switch S3 to
ON
.
(n)
Indication on
TEST
meter M1's lower scale
shall be 30 (3.0) 'Amps'.
(o)
Adjust
O/P PWR
potentiometer A4R31 for the
'intended' carrier level, as indicated by dummy
load's power indicator.
