MAIN/STANDBY 125 WATT RADIOBEACON WITH NDDS/T
(INSTALLED
IN NARB07 CABINET)
IS02001 (Page 9)
29 January 2002
(k) Connect transmitter
B
's original RF output
coaxial cable (wire #33 terminated by P1) to its
RF output connector [it was disconnected in
step (c)].
(l) Restore the standby on/off control. Connect
wires removed in step (b) to their original
destinations (#38 to TB1-6 of transmitter
A
and
#13 to TB1-6 of transmitter
B
).
(m) Select
the
main
transmitter. Set the
SELECT MAIN
TX
switch to the desired setting.
(n) Restore the installation to a main/standby
configuration by setting the
B
transmitter's
POWER
switch to
ON
and its
CONTROL
switch to
LOCAL
or
REMOTE
as desired.
7.2.2 Tx A Under Test/Tx B On-Air:
If the
A
transmitter is to be operated with its RF output into a
dummy load and the
B
transmitter is to be maintained
in an on-air status, proceed as follows:
(a) Turn off both transmitters. Set their
POWER
switches to
OFF
.
CAUTION
Wire #13 and wire #38 have 15VDC on them when
their associated transmitter is turned on. Ensure
terminal lug, of both disconnected wires, does not
contact a conductive surface.
(b) Disable the standby on/off control for both
transmitters. Disconnect wire #38 from TB1-6
of the
A
transmitter and wire #13 from TB1-6 of
the
B
transmitter.
(c) Disconnect
the
B
transmitter's RF output coaxial
cable (wire #33 terminated by P1) from its RF
output connector.
(d) Disconnect
the
A
transmitter's RF output coaxial
cable (wire #34 terminated by P3) from its RF
output connector.
(e) Disconnect the RF output coaxial cable (other
end of wire #34 terminated by P4) from the
interior side of the cabinet's RF output
connector.
(f) Interconnect
the
B
transmitter's RF output
connector and the interior side of the cabinet's
RF output connector, using a suitable coaxial
cable (from coaxial cables provided).
(g) Connect a 250W, precision, 50-ohm, resistive,
dummy load to transmitter
A
's RF output
connector. Use a suitable coaxial cable.
(h) Turn on the
B
transmitter. Set its
POWER
switch
to
ON
.
(i) Set
the
A
transmitter for local control. Set its
CONTROL
switch to
LOCAL
.
(j)
Turn on the
A
transmitter. Set its
POWER
switch
to
ON
.
(k) Test/service the
A
transmitter using the
procedures in the ND500II 125 watt
radiobeacon transmitter instruction manual.
(l) On successful completion of maintenance
procedures, turn off both transmitters. Set their
POWER
switch to
OFF
.
(m) Disconnect and remove the coaxial cable
interconnecting transmitter
B
's RF output
connector to the interior side of the cabinet's RF
output connector [installed in step (f)]
(n) Disconnect dummy load's feed cable from
transmitter
A
's RF output connector.
(o) Connect transmitter
A
's original RF output
coaxial cable (wire #34 terminated by P3) to its
RF output connector [it was disconnected in
step (d)].
(p) Connect the RF output coaxial cable (other end
of wire #34 terminated by P4) to the interior
side of the cabinet's RF output connector [it was
disconnected in step (e)].
(q) Restore the standby on/off control. Connect
wires removed in step (b) to their original
destinations (#38 to TB1-6 of transmitter
A
and
#13 to TB1-6 of transmitter
B
).
(r) If main/standby operation is to be restored,
