Section II. BLOCK DIAGRAM ANALYSIS

C2, TM 11-6625-564-45

(6) T h e + 2 7 . 5 V D C l a m p l i g h t s w h e n

T/R, T/R + G, or ADF lamp of the test unit

will light when the FUNCTION SELECT

the POWER switch is set to RESET

ON. This condition indicates that the

switch is in the respective position.

+27.5-volt dc power supply is sup-

c. The transmit circuitry of the receiver-

plying voltage.

transmitter is keyed when the PTT switch on

f. The radio set simulator provides a head-

the test unit is set to MOM ON or OS. The

set jack and two audio amplifiers to enable

SMIT lamp will light with the switch in either

two-way communication between the techni-

position.

cian in the cockpit and the technician at the

d. W ith the RF DET switch in the OFF pos-

radio set simulator during in-aircraft testing.

ition, the main audio from the receiver-trans-

mitter can be `monitored directly with a head-

Volume may be varied with the AUDIO GAIN

control.

set plugged into the HDSET H-101A U jack.

When the RF DET switch is in the ON posi-

1-5. Signal Paths of Test Set, Radio

tion, the receiver-transmitter transmits into

TS-1962/ARC-51X

jack J3 of the test unit. The signal is detected

(fig. 4-10)

and applied to the HDSET H-101A U jack

where the audio can be monitored by a head-

a. When. Test Set, Radio TS-1962/ARC-

set. The AUDIO GAIN control varies the

51X is used as a signal source for testing the

volume of the audio applied to the headset.

receiver-transmitter, test signals are coupled

c. The test unit contains an audio ampli-

through interconnecting cables to the unit be-

fier that amplifies the headset microphone

ing tested. The output of the unit being

output. This amplified output is applied to

tested is returned through the interconnect-

the modulator and audio module A4 in the re-

ing cables to the test unit. for monitoring. Vari-

ceiver-transmitter.

ous other test equipment may be intercon-

f. The test unit control head contains the

nected also, depending on the test being per-

FUNCTION SELECT switch and the AU-

formed. The front panel provides test jacks,

DIO GAIN control previously described. It

indicators, frequency select switches, and a

also contains FRIEQ SELECT switches and a

function select switch.

SENSITIVITY control. The FREQ SELECT

switches select the operating frequency on the

b. Power is supplied to the test unit from

receiver-transmitter, and the SENSITVITY

the bench through the PWR jack and the

control varies the receiver senitivity. When

POWER switch and circuit breaker. When

the SENSITIVITY control is turned to the ex-

the FUNCTION SELECT switch is turned to

treme clockwise position, marked SQ DIS. the

an operating position (either T/R, T/R+G,

squelch

function

the

receiver-transmitter

or ADF), power is applied to the receiver-

disabled.

transmitter for the respective function. The

Section II. BLOCK DIAGRAM ANALYSIS

T/R+G. or ADF, relay K2 is energized, and

1-6. Simulator, Set, Radio

the input voltage is applied to relay K1. to

transient blanker module 1A.1. and to TEST

(fig. 4-6 and 4-6.1)

SELECT switch S1. When the radio set con-

POWER

When the

a. Primary Power.

trol function select switch is set to T `R.

switch is set to RESET ON, +27.5 VCDC lamp

T/R lamp DS1 will light to indicate that the

receiver-transmitter has +27.5 volts dc with

DS5 lights, and + 27.5 volts dc is applied to

which to operate; when the

switch is set to the

frequency readout mechanism 1A6, relay K2.

T/R + G position. T/R + G lamp DS2 will light

and SMIT LOAD switch S4. When the func-

to indicate that current is flowing through

tion select switch of the radio set control (not

T/R + G lamp DS2, relay K1, and to the guard

shown in figure 4-6) is set either to T/R,