TM 11-6625-2709-40
and P2-e by switch S6C. The completed path of meter
AN/ARN-82B. A schematic diagram of the OBS in-
M2 is through switch S6D to P7-C and P2-q.
b. A r e s o l v e r h a s t h e s a m e e l e c t r i c a l
sh 1 of 3).
characteristics as a transformer. Therefore, a
The COMPASS SIMULATOR indicator contains a
switch S5 is in the BRG position and MODE switch S3
compass in an aircraft installation. As the dial is
is in the 400 HZ position, precision bearing
turned, the synchro generates a varying voltage from
transformers T2 and T3 and their switching circuits
the 26 volts, 400 Hz that is applied to the COMPASS
are used to produce the desired stator voltages. The
SIMULATOR indicator. The output voltage from the
400-Hz reference signal from the radio receiver is
applied through switches S5, S3, and S4 to the
and the RMI card to simulate a magnetic heading.
The pointer simulates the magnetic heading of the
windings simulate the rotor of a resolver.
aircraft.
c. A combination of the precisely tapped secondary
1-10. RMI Circuits (fig 4-12, sh 1 of
3).
windings of transformers T2 and T3 and the
switching arrangement (S4) produces a various
The RMI card gives an indication of simulated
voltage ratio that corresponds to the stator output of
magnetic heading. The simulated magnetic heading
a standard resolver. Each clockwise position of switch
signal originates in the compass simulator, and is
S4 simulates a clockwise rotation of a resolver rotor
routed to the RMI card. The RMI needles give an in-
in precise 30-degree increments. With switch S5 in
dication of the direction of a very-high-frequency om-
the BRG position, the output voltage path from
nirange (VOR) station. In the test set, two needles are
transformers T2 and T3 is through switches S3 and
electrically jumpered together. This makes the two
S5 to the radio receiver on P2-D, -E, -F, and -G.
needles track together. The VOR signals are routed
from the radio receiver to the needle connections on
P4. If the RMI card rotates to indicate a magnetic
heading, the needles will follow the card rotation to
The outputs of four circuits in the radio receiver are
keep in the direction of the VOR station. For more in-
measured in the test set. These measuring circuits are
formation on the RMI, refer to TM 11-5826-211-50 for
described below.
RMI Indicator ID-250A/ARN. The RMI is shown in
a. To-from current from the radio receiver is read
on meter M3. TO-FROM meter M3 indicates the direc-
1-11. Aid
Box
tion and amplitude of the current. Resistor R8 is a
shunt resistor to provide normal to-from loading.
is primarily intended for testing a new
b. Deviation current from either the radio receiver
harness, hut it can he used for a quick check on the
or the glideslope receiver is read on meter M1. With
test set. The main circuits are as follows:
switch S6 in the RCVR V/L position, P2-m, P, and B
a. Light Circuitry. The
light circuitry is
provided
connect through switch S6A to the DEVIATION
to indicate when a circuit is made complete or when it
meter. The return path from meter M1 is through
is energized. Frequency control information is given
switch S6B to J2-n. When switch S6 is in the RCVR
in a code by the lamps. The lamps that check the
G/S position, P7-D and J2-r connect through switch
power circuits glow when a current flows through
S6A to the DEVIATION meter. The completed path
them, indicating an energized circuit.
of meter M1 is through switch S613 to P7-E and P2-s.
b. Meter Circuitry. The 26
volts, 400 Hz is
applied
to J1-G and is routed to zener diode CR1, Resistor R8
c. Flag current from either the radio receiver or
and zener diode CR1 form the 10-volt dc power supply
the glideslope receiver is read on FLAG meter M2.
for the meter circuits. Resistor R6 is a current-
When switch S6 is in the RCVR V/L (very-high-
limiting resistor for the TO-FROM meter. Resistor R5
frequency omnidirectional radio range/localizer)
is a current-limiting resistor for the DEVIATION
position, meter M2 is connected through switch S6D
meter. Resistor R3 (a 511-ohm load) and resistor R4 (a
to P2-b. The completed path from the meter is
1000-ohm load) are the loading resistors for the
through switch S6C to P2-a. With switch S6 in the
DEVIATION meter. Resistor R2 is the current-
RCVR GS position, meter M2 is connected to P7-B