Set controls on test equipment.

Troubleshoot and Repair Communications System Control
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(5)

Connect voltmeter ME-30A/U to J20 on the MK-994/AR. Use a plug-in adapter

as you did in the previous step.

(1)

Set the front panel controls on the MK-994/AR. (Refer to TM 11-6625-928-12, if

needed.)

(2)

Set the COMM control 2 (C-6533 being tested) as follows:

(a)

Receivers 1 through 5 to OFF.

(b)

AUX and NAV receiver to OFF.

(c)

VOLUME control fully clockwise.

(d)

FUNCTION SELECTOR switch to ICS.

(e)

HOT MIKE to OFF.

Perform the functional test (three simple steps).

(1)

Turn the POWER switch on facilities kit MK-994/AR to the ON position. (The DC

power lamp on the test set should light red. If it does not, notify your instructor.)

(2)

Test the microphone amplifier.

(a)

Hold the MK-994/AR headset 2 switch in the INTERCOM position and speak into

the headset 2 microphone.

(b)

You will hear the sound of your voice in the headset 1 earphone and at a

reduced volume in the headset 2 earphone. Should the test fail and little or no audio is heard

in headset 1 earphone, you have a probable fault in the microphone amplifier circuit.

NOTE:

Refer to Table 1, code 0|1. (See page 3-4, TM 11-5821-262-35 extract.)

(3)

Test the headset amplifier.

(a)

Hold the MK-994/AR headset 1 switch in the INTERCOM position. Speak into

the headset 1 microphone.

(b)

You will hear the sound of your voice in the headset 2 earphone. Should the

test fail and no audio is heard in the headset 2 earphone, you have a probable fault in the

headset amplifier circuits.