500 WATT RADIOBEACON TRANSMITTER
ND2000A-02x-xx0
Page 5-3
15 January 2005
(a) Verify the requirements of paragraph 5.3.2 have
been completed and are being met.
(b) Verify AC power source voltage is within five
percent of voltage used to select the primary
winding taps of power transformers A7T1 and
A8T1 (see paragraph 3.9.4).
(c) Verify ac power is turned on at the service
entrance and is being applied to transmitter.
(d) Set
POWER-AC LINE
switch A6S1 to
ON
.
(e) All lamps shall be off.
(f) Set power supply module A's
POWER-AC LINE
switch (A7S1) to
ON
.
(g)
DC SUPPLY
lamp A7DS2 and B- lamp
A2A9DS1 shall turn on.
(h) Set power supply module B's
POWER-AC LINE
switch (A8S1) to
ON
.
(i)
DC SUPPLY
lamp A8DS2 and B- lamp
A3A9DS1 shall turn on.
(j)
All other lamps shall be off.
5.3.4
DC VOLTAGE CHECKS:
Check the B-
voltage (no load) and logic/control dc voltages as
follows:
5.3.4.1
B- Voltage (No Load) Check:
Check the
no load B- voltage level as follows:
(a) Verify switches are set as tabulated for
Test
Settings
in table 4-1.
(b) Verify
O/P POWER
potentiometers A4A2R48
(A5A2R48) are set fully counter clockwise.
(c) Connect a multimeter between test point
A7A1TP1 (A8A1TP1) and ground.
(d) Indication on multimeter should be precisely -
51.0 V dc.
(e) If
necessary,
adjust
B- Level
potentiometer
A7A1R12 (A8A1R12) for a multimeter
indication of precisely -51.0 V dc.
(f) Set
TEST-Volts/Current
switch to
B-V - SIDE A
(
B
).
(g)
TEST-Volts/Current
meter indication shall be
between -50.0 and -52.0 V dc.
NOTE
Adjustment of
Meter Cal
potentiometer affects
TEST-
Volts/Current
meter's +24, +15 and -15 indications.
(h) If necessary, adjust
Meter Cal
potentiometer
A1A1R2 for a
TEST-Volts/Current
meter
indication of -52.0 V dc.
5.3.4.2 Logic/Control Dc Voltage Checks:
Check the logic/control dc voltages as follows:
(a) Verify requirements of paragraphs 5.3.2 and
5.3.3 are completed and being met.
(b) Set
RF
switch to
ON
.
(c)
RF CURRENT-ALARM
lamp,
RF ON
lamp,
MONITOR-BYPASS
lamp and
CON24V
lamp A7DS1 (A8DS1) shall turn
ON
.
(d)
AUDIO LIMITER
lamp A4DS1 (A5DS1) and
RF
DRIVE-ALARM
lamp A4DS2 (A5DS2) will turn
on initially. After a delay of approximately five
seconds, they shall both turn off.
(e) Blower fan A2B1 (A3B1) shall turn on and
circulate cooling air.
(f) Set
TEST-Volts/Current
switch to
+24V - SIDE A
(
B
).
(g) Connect a multimeter between meter M2 (+)
and ground.
(h) Multimeter's indication shall be between 23.8
and 24.2 V dc.
(i) If
necessary,
adjust
24 VDC Level
potentiometer
A2A1R10 on power supply A7 (A8), for a
multimeter indication of 24.0 ± 0.2 V dc.
(j)
TEST-Volts/Current
meter's indication shall be
within 10% of the reading in step (h).
(k) Record difference between reading obtained in
step (h) and reading obtained in step (j) as
TEST-
Volts/Current
meter's correction factor for
+24
VOLTS
in
Established References
section of
table 5-2.
