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Figure 1-6. Audio Amplifier  A1 (located in TS­1967/ARC-54), simplified schematic diagram
TM-11-6625-601-34 Maintenance Kit Electronic Equipment MK-733/ARC-54 (NSN
Figure 1-7. Rf power-measuring circuit, simplified schematic diagram
TM 11-6625-601-34
through resistor R21 and capacitor C12 to the
J37 and J38 to contacts of relays K2 and K3,
base of emitter follower Q5.
respectively. From the contacts of relays K2 and
b. Incoming audio is applied, through VOL
K3, respectively. From the contacts of relays K2
control R4, resistor R22, and capacitor C13, to
and K3, the rf signal is applied through plugs
the base of emitter follower Q5.
P 1 3 and P14 to attenuators AT4 and AT6,
c. Audio from emitter follower Q5 is applied
respectively, which reduces the rf signal an
t h r o u g h capacitor C14 and terminal 78 to
additional 6 db. The attenuated rf signal (down
HEADSET jack 7.
12 db from the input of the signal) is then
t h r o u g h jacks  J44  and  J45  of
1­14. Rf Power-Measuring Circuit
attenuators AT4 and AT6, and the contacts of
relays K2 and K3, to home left J14 and home
The rf power-measuring circuit in the
right jack J13, respectively. The equal level of
the rf signal applied to jacks J14 and J13
coupler, a function selector switch, two calibra-
simulates an on-course heading. Setting HOME
tion potentiometers, and an rf power meter. Rf
S I M U L A T O R switch S1A (rear) to LEFT
applies ground through contacts 3 and 1 of
power applied to DIR COUPLER IN jack J3 is
routed through plug P1 to directional coupler
switch S1A (rear) to terminal 1 of relay K2.
DC1. From directional coupler DC1, the main
Relay K2 energizes, removing attenuator AT4
portion of the input rf power is applied through
from the circuit and connecting attenuator AT5
plug P2 to DIR COUPLER OUT jack J6. A small
in series with the output. The resultant rf signal
portion of the rf power, incident (output) and
applied to home left jack J14 is attenuated 9 db
reflected, is detected by the diodes in directional
instead of 12 db as before. This simulates a left-
coupler DC1, resulting in a dc voltage propor-
course heading. Setting switch S1A (rear) to
RIGHT removes ground from relay K2, causing
tional to the incident and reflected power levels.
K 2 to reenergize.  G r o u n d is then applied
From directional coupler DC1, the dc voltage is
applied to contacts 6, 4, and 7, 5, respectively,
through contacts 8 and 10 of switch S1A (rear)
of POWER/VSWR switch S2. Setting switch S2
to terminal 1 of relay K3. Relay K3 energizes,
to FWD applies dc voltage proportional to the
removing attenuator AT6 from the circuit and
incident rf power level, through contacts 4 and
connecting attenuator AT7 in series with the
12 of switch S2 and power calibrate potentiome-
output. The resultant rf signal applied to home
ter RI, to RF POWER meter M1. (Potentiometer
right jack J13 is attenuated 9 db instead of 12
R1 is used to calibrate meter M1 for the proper
db as before. This simulates a right-course
reading of a known amount of input rf power.)
Setting switch S2 to REFL applies dc voltage
1-16. Power Distribution Circuit
proportional to the reflected rf power, through
contacts 5 and 1 of switch S2 and potentiometer
R1, to meter M1. Setting switch S2 to CAL
Operating voltage of +27.5 volts dc is obtained
applies dc voltage proportional to the incident
from an external power source. The +27.5 volts
rf power, through contacts 6 and 2 of switch S2
dc is applied through POWER 28V DC jack
and VSWR CAL potentiometer R2, to meter M1.
J32 to power circuit breaker CB1 in the test set.
(Potentiometer R2 is used to position the meter
From circuit breaker CB1, +27.5 volts dc is
needle to CAL.) Setting switch S2 to VSWR
circuits  in
routed  to
applies dc voltage proportional to the reflected
rf power, through contacts 7 and 3 of switch S2
C-3835/ARC-54, the RT-348/ARC-54, and the
and potentiometer R2, to meter M1.
CU-942/ARC-54 or the CU-943/ARC-54.
a. Routing of Voltage in Test Set, Radio
Test  Set,
Radio TS-1967/ARC-54
TS-1967/ARC-54. Closing circuit breaker CB1
Homer Signal Circuit
applies +27.5 volts dc to pin a of CONT UNIT
jack J16, pin 2 of lamp DS1, and contacts 10 and
The homer signal simulator circuit in the test
S11D (rear) and S11F (front), respectively.
set consists of two relays, three 6-decibel (db)
With switch S11 set to TEST SET, +27.5 volts
attenuators, two 3-db attenuators, and a func-
dc is routed to terminals 11 through 15 of termi-
tion selector switch. An rf signal applied to
nal board TB1 from contacts 8 and 5 of switches
HOME INPUT jack J1 is routed through plug
S11D (rear) and S11F (front), respectively. The
P20 to attenuator AT3. Attenuator AT3 reduces
the rf signal 6 db and applies it through jacks
+27.5 volts dc applied to terminal 10 of TB1 is

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