Section V. BENCH TESTS

TM 11-5826-257-24

instrument panel must light, and the MIDDLE

c. Set the BC-376 MODULATION switch to

and OUTER lamps must not light.

1300. The MIDDLE marker lamp on the aircraft

instrument panel must light, and the OUTER and

NOTE

AIRWAY lamps must not light.

Test must be performed with aircraft

away from electromagnetic energy and

reflecting surfaces such as buildings or

d. Set the BC-376 MODULATION switch to

other aircraft.

3000. The AIRWAY marker lamp on the aircraft

BENCH TESTS

Section V.

Table 4-3. Pretest resistance check

414. General

Resistance

VOM range

P1 pin

a. This section contains bench testing proce-

setting

measured (ohms)

number

dures for the receiver. The test procedures specify

X1K

50K (rein)

the minimum performance limits within which

50K (rein)

X1K

the receiver may operate and still be suitable for

30K (rein)

X1K

installation in an aircraft. As such, the tests may

1K (rein)

X1K

be used to check a unit which has been removed

0.1 (max)

50K (rein)

X1K

from an aircraft or a unit which has been in

X1K

50K (rein)

storage.

b. If the receiver tests within the acceptable

plug P7 mates with jack J7 on the Receiver

limits given, no further testing is required and

Adapter Cable CX-13035/AR. Plug P11001 on the

the receiver may be considered suitable for instal-

receiver adapter cable connects to J1 on the

lation in an aircraft.

receiver panel.

(2) The radio test set must be connected to a

c. If the unit fails to meet any requirement of

the tests, all further tests need not be performed

115 vac 400 Hz power source (gray wire, high).

and the receiver must be returned to the manu-

The red wire from the radio test set must be

facturer for corrective action under the equip-

connected to a 28 vdc power source. The black,

ment warranty.

white, and green wires from the radio test set are

ground wires, and must be connected to a common

ground.

NOTE

b. Initial Switch Settings. Before performing

Personnel must be aware that any at-

the glideslope bench test procedures, the controls

tempts at maintenance beyond the test-

of all items of test equipment should be set as

ing specified herein will void the manu-

follows:

facturer's warranty.

Radio Test Set AN/ARM-92B

PWR

OFF/PWR/TEST

4-15. Preliminary Procedures

400 Hz

MODE

The following general test conditions must be

BEARING control

observed:

BRG

BEARING switch

a. Receiver chassis must be grounded.

FLAG LOAD

b. Before connecting the receiver to the radio

SENS

test set, check the resistance of the pins listed in

GS RCVR

IND TEST

table 4-3 by connecting multimeter AN/URM-223,

DEVIATION

or equivalent, between the pin and the receiver

109.30

CONTROL frequency

chassis. The negative lead must be connected to

Radio Test Set AN/ARM-5

the receiver chassis.

STAND BY

POWER

c. Allow 1 minute warmup time.

OMNI TRACK

AMP LOC

MODULATION

4-16. Glideslope Bench Tests

OFF

IDENTIFIER

a. Test Setup.

ATTENUATOR

(1) All bench tests are performed with the

test setup shown in figure 4-1. Coaxial cables with

Frequency Converter AN/ARM-69

OFF

52 ohms characteristic impedance are used for all

POWER

332.0

rf and modulation interfaces. The test set cable

FREQ MC

4-4