Sectionalizing Test Settings.

TM 11-5820-509-35

the dummy load using the 3-foot length of RG-58/U

b. Sectionalizing Test Settings.

coaxial cable from the AN/PRA-4.

(1) General.

The extender cables and

(c) Connect the multitester (with rf

components of Cable Assembly Set AN/PRA-4 are used

probe attached) to the VTVM terminals of the antenna

during the bench tests of Radio Receiver-Transmitter

simulator using the 5-foot length of RG-58/U coaxial

RT-671/PRC-47. For these tests it is not necessary to

cable.

remove and extend the modular subassemblies, but the

dust cover must be removed to gain access to the test

(d) Connect the primary power source

points at the top of each module and beneath the power

to be used to the POWER connector on the front of RT-

amplifier compartment. Remove the dust cover using

671 /PRC-47.

the procedures listed in paragraph 3-11.

The

(e) Adjust the control knobs to provide

troubleshooting checks for the receiver portion of the

a reading of 3002 on the KILOCYCLES indicator on the

equipment differ greatly from those specified for the

front of RT-671/PRC-47; then place the CW-

transmitter circuits, and the test setup conditions

FSK/VOICE switch to VOICE, the XMTR PWR switch to

likewise differ. Use the appropriate setup and initial

LO, and the OPR-TUNE switch to OPR.

procedures described in steps (2) and (3) below.

c. Sectionalizing

Trouble.

The

following

CAUTION

procedures sectionalize the malfunction to the power

Do not key the transmitter unless the

distribution, receiver-transmitter, frequency generation,

rf output is terminated in a 50-ohm

or relay control circuits of the RT-671/PRC-47. If a

dummy load, a quarter-wave whip, or

specific symptom is indicated by the intermediate

a suitable long-wire antenna. Never

preventive maintenance checks and services performed

key the transmitter while Signal

at the organizational level, or by the short circuit tests of

Generator

SG-103/URM-25F

paragraph 3 4 a(4). enter the chart in that functional

connected to the ANTENNA terminal

area; otherwise, perform all steps.

of the RT-671 /PRC-47.

CAUTION

(2) Receiver Test Setup and Initial Settings

Do not perform these checks unless

(fig. 3-2).

the short circuit tests indicate that

further damage to the equipment is

(a) Connect the dummy load (or a 50-

unlikely.

ohm noninductive resistor) to the ANTENNA terminal of

RT-671/PRC-47 using the antenna test lead from the

(1) Preliminary Procedures.

AN/PRA-4.

(a) Energize the primary power source

(b) Connect the signal generator to the

(if separately controlled); then rotate the POWER -

ANTENNA terminal.

LIGHTS switch on the front panel of RT-671/PRC-47 to

the POWER ON position.

(c) Connect the primary power source

to be used to the POWER connector on the front of RT-

(b) Press the BATTERY TEST switch

671 /PRC-47.

on the front panel of RT-671/PRC-47 and observe that

the XMTR OUTPUT meter reads in the banded area of

(d) Connect a 300-ohm audio load to

its scale. {If this indication is not obtained, perform the

pin L of AUDIO connector on the front panel of RT-

power distribution circuit checks before proceeding

671/PRC-47; then attach multitester leads across this

further.)

resistor.

(2) Troubleshooting Chart.

(e) Set the front panel controls and the

test equipment conditions as directed in the chart of

CAUTION

paragraph 3-4 c (2).

Do not place the CW-FSK/VOICE

switch to CW-FSK in any of the

(3) Transmitter Test Setup and Initial Settings

following tests unless the transmitter

( fig. 3-3 ).

output is properly terminated in a

(a) Connect

the

RT-671/PRC-47

dummy load or a suitable antenna

ANTENNA terminal to the antenna simulator of AN

system. Never switch to CW-FSK

/PRA-4.

when the signal generator is

(b) Connect the antenna simulator to

connected to the ANTENNA terminal.

3-73