TM 11-6625-820-45
anywhere from 0 to 360, but precision bear-
R e c e i v i n g Sets AN/ARN-82 and AN/ARN-
ing transformer T2 shifts the phase of the sig-
82A (receiving set) when used with external
nal in precise 30 increments. The exact 30 in-
T h e test set can also be
test equipment.
u s e d to test a glide-slope receiver, and
crement is selected by BEARING switch S3.
provides for flag and deviation loading. The
d. Current Measuring Circuits. T O - F R O M
g l i d e - s l o p e test requires a special cable
meter M3 connects directly to the radio receiver
that is not supplied with this unit. The func-
and measures its to-from current. DEVIATION
tions of Test Set, Radio AN/ARM-92A are:
meter M1 and FLAG meter M2 are connected
(1) Power distribution.
either to the radio receiver or to the glide-slope
(2) Phase shifting.
receiver, depending on the position of VOR/
(3) Resolver signal transmission.
LOC-GLIDE SLOPE switch S1. These two
(4) Current measuring.
meters measure the deviation current and flag
(5) Compass simulation.
current from either receiver. The FLAG meter
(6) Self-test of control unit and functions
also measures the output of the RMI servoam-
of the test set.
plifier in the radio receiver. When SERVO
b. Power Distribution Circuits. Control, Ra-
AMP TEST pushbutton switch S4 is pressed,
dio Set C-6873/ARM-82 (control unit), power
it connects 27.5 volts dc to the RMI servoam-
relay K1, and power transformer T1 com-
plifier and to flag meter relay K2. The flag
prise the power distribution circuits.
The
meter relay energizes and connects FLAG me-
t e s t set connects 27.5 volts direct current
ter M2 to the RMI servoamplifier output of the
(dc) from an external power source to the
radio receiver.
c o n t r o l unit which applies or removes the
e. Compass Simulator Circuit. C O M P A S S
27.5 volts dc from the remaining power cir-
S I M U L A T O R DS4 simulates a magnetic
W h e n the control unit applies this
cuits.
heading signal which is applied to the radio
voltage to the remaining power circuits, 27.5
receiver. The simulated magnetic heading sig-
volts dc is applied to Radio Receiver R-1388/
nal is also applied to Indicator, RMI ID250A/
A R N - 8 2 (radio receiver), or to the glide-
ARN on the test set to drive the RMI card.
slope receiver, and to power relay K1. The
f. Aid Box. The aid box checks the wiring
relay then energizes and connects 115 volts,
harness in an aircraft installation of Radio Re-
4 0 0 Hz to power transformer T1. Trans-
ceiving Set AN/ARN-82, and checks the con-
former T1 steps the voltage down to 26 volts,
trol unit installed in the test set or aircraft.
400 Hz, which is applied to the radio receiv-
It also provides a quick check of the accuracy
er. The control unit also supplies the tuning
of the meters in the test set. The aid box re-
information required by the radio receiver,
ceives frequency information from the con-
or the glide-slope receiver.
trol unit in the test set or aircraft. This fre-
quency information lights the lamps on the aid
c. Phase Shifting Circuits. T h e p h a s e
box in specific combinations. The aid box also
shifting circuits (consists of precision bear-
receives 26 volts, 400 cps from the test set or
ing transformers T 2 a n d T 3 ; I n d i c a t o r ,
from the aircraft. A portion of this voltage is
Course ID-1347/ARN-82 (OBS); RECEIVER
rectified, and then divided to specific levels.
MODEL switch S5; BEARING switch S3; and
Specific levels of dc voltage are applied to the
BRG-OBS switch S2.
These circuits are
meter circuits in the test set or to the aircraft
used to shift the phase of the 30-Hz refer-
indicators. A portion of the 26 volts, 400 cps
e n c e signal obtained from Radio Receiver
E i t h e r the OBS resolver
is also used to check the audio wiring.
R-1388/ARN-82.
or precision b e a r i n g transformer T2 per-
forms the phase shifting; BRG-OBS switch
1-2.1. Block Diagram Functioning of
S2 selects the one to be used. The OBS re-
T e s t Set, Radio AN/ARM-92A
solver shifts the phase of the 30-Hz refer-
ence signal anywhere from 0 to 360, preci-
a. General. Test Set Radio, AN/ARM-92A
sion bearing transformer T2 shifts the phase
provides for the complete testing of Radio
of the signal in precise 30 increments. The
C h a n g e 2 1-2.1
