General Test Requirements

101. General Test Requirements

b. Connect a test cable No. 7 from ground of

power supply A (2.5 volts) to terminal D of test

Most of the tests will he performed under the

assembly terminal board TB1.

conditions listed below and illustrated in figure 79.7

c. Connect a test cable No. 7 from the positive

(for the receiver system tests) and in figure 79.8 (for

output of power supply A (2.5 volts) to terminal E

the transmitter system tests). Testing will be

of test assembly terminal board TB1.

simplified if preliminary standard control settings

d. Connect a test cable No. 7 from ground of

are made initially and changes from these settings

power supply B (12.5 volts) to terminal D of test

are then made as required for the individual tests.

assembly terminal board TB1.

Perform all tests in Enclosure, Electromagnetic

e. Connect a test cable No. 7 from the positive

Shielding MX-1761/C (or equivalent). Do not

output of power supply B (12.5 volts) to terminal F

apply power to the equipment under test until all

of test assembly terminal board TB 1.

test connections are made and the power supply

f. Connect a test cable No. 4 from the AF input

output voltages are set.

terminal of TS-723A/U (shield to ground) to

Caution: When adjusting the power supply

terminals C and D (shield) of test assembly terminal

output voltages, do not exceed 3 volts and 15 volts.

board TB1.

a. Remove the shorting cap from POWER con-

g. Connect a test cable No. 4 from the audio

nector J3 on the front panel of the RT-505/PRC-25.

input terminals to the meter terminals of the TS-

b. Loosen and disengage the four captive screws

723A/U.

that hold the case to the front panel of RT-505/

h. Connect a test cable No. 4 from the af input

PRC-25. Remove the case.

terminals of the TS-723A/U to the vertical input

c. Connect the RT-505/PRC-25 into the appli-

of the AN/USM-50A.

cable test setup (fig. 79.7 for receiver system tests

i. Connect the receiver dummy antenna to the

and fig. 79.8 for transmitter system tests).

RT505/PRC-25 coaxial ANT jack J2. Use

d. Apply power to the RT-505/PRC-25 and

Adapter, Connector UG-491A/U for connection to

allow sufficient stabilization (warmup) time for the

ANT jack J2.

test equipment. Five minutes is adequate for the

j. Connect test cable No. 9 from the receiver

RT-505/PRC-25.

dummy antenna to the 1066A RF input.

e. All specified signal levels apply to the signal at

k. Connect test cable No. 8 from the 1066A

the RT-505/PRC-25 input and not at the signal

external modulation input to the HP-200AB

generator output. The dummy load used in the

audio output.

receiver test setup reduces the rf voltage delivered

l. Connect test cable No. 5 from the HP-200AB

at the coaxial ANT connector to half of the signal

audio output to the AN/USM-26 signal input.

generator output attenuator setting (6 db loss).

m. Do not turn on the RT-505/PRC-25. Turn on

f. The oscilloscope used in test setups is included

all test equipment and allow sufficient warmup time.

for the convenience of maintenance personnel, but

n. Adjust power supply A to 2.5 volts and power

is not necessary to perform the tests. It provides a

Supply B to 12.5 volts.

convenient output indication for both receiver and

o. Set the RT-505/PRC-25 function switch to

transmitter tests.

ON and select a frequency of 41.00 mc. Allow 5

g. ln all receiver tests, set the signal Generator

minutes to warmup.

F. M. Marconi Model 1066A (1066A) frequency to

p. Adjust the 1066A to produce an RF output of

produce minimum distortion (as read on the TS-

41.00 mc at a 20-microvolt level with 10-kc de-

723A/U) before making any readings.

viation at 1,000-cps modulation frequency.

h. To avoid audio ground loops, do not ground

Note. The dummy antenna used in series with the 1066A

Audio Oscillator Hewlett-Packard Model HP-200AB

output provides 6 db of attenuation. The actual RF level

(HP-200AB) output to the common ground at any

delivered at the RT-505/PRC-25 coaxial ANT input is

10 microvolt when the 1066A output attenuator is set to

point.

20 microvolt.

102. Receiver Test Setup

q. Adjust the RT-505/PRC-25 VOLUME con-

(fig. 79.7)

trol to produce a l-volt reading on the TS-723A/U

(used as a vacuum-tube voltmeter).

a. Plug the test assembly connector PL into

V. Perform the receiver system tests indicated in

POWER connector J3 on the front panel of the

paragraph 104.

RT-505/PRC-25.

TAGO 8344-A