Transmitter Test Setup

103. Transmitter Test Setup

on the test assembly and the HP-200AB output

(fig. 79.8)

level to produce a 1.4-millivolt reading on the

ME-30A/U.

a. Plug the test assembly connector into POWER

s. Perform the transmitter system tests indicated

connector J3 on the front panel of the RT505/

in paragraph 105.

PRC-25.

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

104. Receiver System Tests, Radio Set AN/

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

PRC-25

assembly terminal board TB1.

a. Sensitivity Test.

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

(1) Perform the sensitivity test with the

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

equipment connected in a standard re-

of test assembly terminal board TB1.

ceiver test setup (para 102 and fig. 79.7),

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

except set the RF signal level at the RT-

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

505 /PRC-25 coaxial ANT input to 0.6

assembly terminal board TB1.

microvolt.

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

(2) Measure the signal-plus-noise-plus-distor-

output of powersupply B (12.5 volts) to terminal F

tion to noise-plus-distortion ratio on the

of test assembly terminal board TB1.

TS-723A/U, and record. The ratio should

f. Connect a test cable No.4 from the HP-200AB

be at least 10 db.

audio output to test assembly terminals A and B

(3) Adjust power supply A to 2.25 volts,

(shieId) of terminal board TB1.

power supply B to 10.0 volts, and repeat

g. Connect test cable No. 4 from the ME-30A/U

the procedure given in (2) above.

input to test assembly terminals A and B (shield)

(4) Adjust power supply A to 3.0 volts, power

of terminal board TB 1.

supply B to 15 volts, and repeat the pro-

h. Connect a test cable No. 2 from coaxial ANT

cedures given in (2) above.

jack J2 of the RT-505/PRC-25 to the input of the

(5) Repeat the procedures given in (2), (3), and

Attenuator, Adjustable "T", General Radio Type

(4) above at 65 mc.

GR-874-GA (adjustable attenuator).

(6) Repeat the procedure given in (2) above

i. Connect test cable ATO. 3 from the unattenuated

at 30.00, 52.00, 53.00, and 75.95 mc.

output of the adjustable attenuator to the input

b. Distortion, Audio Power Output, Volume Con-

of the AN/URM-43A.

trol, and Audio Frequency Response Tests.

j. Connect a test cable No. 2 from the attenuated

(1) Perform these tests with the equipment

output of the adjustable attenuator to the ME-57/U

connected in a standard receiver test

input through adapter UG-274/U.

setup (para 102 and fig. 79.7).

k. Connect test cable 9 from the AN/USM-26

(2) Measure the percentage of distortion on

input, through adapter UG-274/U, to the ME-

the TS-723A/U. Maximum allowable

57/U input.

distortion is 6 percent.

l. Connect a test cable No. 4 from the ME-57/U

(3) Adjust the VOLUME control on RT-505/

audio output to the TS-723A/U input.

PRC-25 to produce a 2-volt reading on

m. Connect a test cable No. 4 from the ME-57/U

the TS-723A/U (used as a vacuum-tube

audio output to the AN/USM-50A vertical input.

voltmeter).

n. Connect a test cable No. 4 from the audio input

(4) Measure the percentage of distortion on

terminals to the meter terminals of the TS-723A/U.

the TS-723A/U. Maximum allowable

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

distortion is 10 percent.

all test equipment and allow sufficient warmup

(5) Set the VOLUME control on the RT-505/

time.

PRC-25 fully clockwise. The output

p. Adjust power supply A to 2.5 volts and power

indicated on the TS-723A/U (used as a

supply B to 12.5 volts.

vacuum-tube voltmeter) should be at

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

least 2 volts.

ON and select a frequency of 41.00 mc. Allow 5

(6) Set the VOLUME control on RT-505/

minutes to warmup.

PRC-25 fully counterclockwise and dis-

r. Adjust the HP-200AB to 1,000 cps. Adjust the

connect the RF output cable from the

TRANSMITTER AUDIO INPUT LEVEL control

1066A. The output indicated on the TS-

TAGO

8344-A