Preliminary Subsystem Test

TM 11-5895-833-12/NAVELEX 0967-LP-550-1010/TO 31R5-2TSC54-91

Position

Indication

observe that the RF LO FAULT INDICATOR lamp

STD LVL

Blue scale

illuminates.

5 MHz INTL STD

Blue scale

70 MHz INTL STD

Blue scale

NOTE

p. Set up-converter RF OUTPUT switch to OFF-LINE.

Detune to assure RF LO FAULT IN-

q. Adjust RF POWER meter upper and lower limit

DICATOR is operational.

controls to position limit pointers at upper and lower

extremes of meter scale.

y. Set STATUS SELECTOR switch to RF LO TUNE

r. Set up-converter POWER ON-OFF circuit breaker

and adjust RECEIVE FREQUENCY FINE TUNE control

to ON. The POWER ON indicator lamp should illuminate.

for center-scale indication on STATUS meter. The RF

The RF LO FAULT INDICATOR lamp may illuminate.

LO FAULT INDICATOR lamp should extinguish.

z. If required, slide down-converter into cabinet and

NOTES

tighten captive screws.

The up-converter is operational as soon as

aa. Repeat the procedures outlined in v through z

it is turned on; however, a 1-hour warmup

above for all remaining down-converters.

period should be allowed to achieve

maximum stability.

3-6. Preliminary Subsystem Test

Should RF LO FAULT INDICATOR lamp go

on at loss of rf oscillator phase lock, when

The preliminary subsystem test uses test translator 1A5

phase lock is reestablished light may flash

as a satellite substitute to simulate an operational

for a period not to exceed 180 seconds

situation. During the performance of the test, the 70-MHz

before extinguishing.

test output of the test translator is applied to an up-

s. Set up-converter TRANSMIT

FREQUENCY

converter where it is converted to a transmit band

SELECTOR MHz switch to 8250.000 and observe that

frequency. The transmit band output of the up-converter

the RF LO FAULT INDICATOR lamp illuminates.

is translated to a receive band frequency by the test

(Detune to assure that RF LO FAULT INDICATOR is

translator for application to a down-converter. The down-

operational.)

converter converts the receive band frequency to a 70-

t. Set status selector switch to RF LO TUNE and

MHz signal. In the preliminary subsystem test, the

adjust TRANSMIT FREQ FINE TUNE control for center-

transmit frequency of 8250 MHz is chosen so that the

scale indication on STATUS meter.

translated receive frequency of 7525 MHz will be

u. Repeat the procedures outlined in p through t above

accepted by either down-converter split band input filter

for all remaining up-converters.

A7FL1 or A7FL2.

v. Set down-converter POWER ON-OFF circuit

breaker to ON. The POWER ON indicator lamp should

NOTE

illuminate. The RF LO FAULT INDICATOR lamp may

Although this test is performed with a 70

illuminate and the audible alarm may sound.

MHz if. test signal input, the tests may also

w. If necessary to silence the audible alarm, loosen

be performed on wide-band if. converters.

captive screws, slide down-converter out of cabinet, and

However, the 700-MHz if. converter circuits

pull out audible alarm interlock switch S5 (located on

are not fully exercised. Complete testing of

extreme lower right-hand side of rear panel).

wide-band if. converters is accomplished at

direct support maintenance.

NOTE

The down-converter is operational as soon

a. Interconnect the test translator, the up-converter

as it is turned on; however a 1-hour

under test, and the down-converter under test as shown

warmup period should be allowed to

in figure 3-10.

achieve maximum stability.

b. Connect up-converter under test with at least 10 db

x. On down-converter front panel, set RECEIVE

of attenuation in the IF level attenuator and down-

FREQUENCY SELECTOR MHz switch to 7525.00 (MHz)

converter under test as shown in figure 3-10 using the

TUNE

position

and

up-converter test output jack J2 and down-converter test

input Jack J3 (on the front panel).

Change 1 3-15