Maintenance Kit Operating Switches, Controls, Indicators, and Jacks

TM 11-6625-1635-12

Switch, control, indicator,

Function

jack or fuse

Turns the AN/ARC-134 audio output on and off.

AUDIO switch

In the ON position, the AN/ARC-134 squelch circuit is disabled, per-

SQUELCH DISABLE switch

mitting signal levels below the squelch threshold to be heard.

In the ON position, the AN/ARC-134 squelch can be adjusted by

EXT SQUELCH CONT switch

means of the test panel EXT SQUELCH CONT

Adjusts the AN/ARC-134 squelch when the EXT SQUELCH CONT

EXT SQUELCH CONT

switch is set on ON.

Indicator Lamps

Lights when 27.5 Vdc power is applied to the maintenance kit and

27.5 Vdc

the POWER switch is set to ON.

(maintenance kit modified)

Lights when 28.7 Vdc power is applied to the maintenance kit and

28.7 Vdc B +

the POWER switch is set to ON.

(maintenance kit unmodified)

Lights when 5-volts ac power is applied to the maintenance kit and

5 Vac

the POWER switch is set to ON.

(maintenance kit unmodified)

Powerline fuses. Protect the dc circuits in the maintenance kit and

250 V 10A fuses

AN/ARC-134.

Powerline fuse. Protects the ac circuits in maintenance kit.

250 V 1A fuse (maintenance kit unmodified)

Keys the AN/ARC-134 when set to ON.

PTT switch

Provides circuit connections for keying and modulating the AN/

MIKE jack

ARC-134 with an external carbon microphone.

Provide connections to a 100-ohm input circuit for modulating the

MIKE INPUT jacks

AN/ARC-134 with an external audio test signal.

Provide connections to a 500-ohm center-tapped microphone input

DBM INPUT jacks

circuit for modulating the AN/ARC-134 with an external audio

test signal.

Provide connections to the ATCSSa input circuit for modulating the

DATA LINK INPUT jacks

AN/ARC-134 with an external audio test signal.

Provides a headset connection.

RECEIVER OUTPUT jack

Provide connections for an audio voltmeter.

RECEIVER OUTPUT jacks

Provide connections to the ATCSSa output circuit in the AN/ARC-

DATA LINK OUTPUT jacks

134.

Provides a headset connection.

SIDETONE jack

Provide connections for an audio voltmeter.

SIDTONE OUTPUT jacks

Used to connect the AN/ARC-134 output to the input of a detector

DETECTOR INPUT jack

circuit in the maintenance kit.

Provide connections from the output of a detector circuit in the

DETECTOR METER jacks

maintenance kit to an audio voltmeter, permitting measurement

of the AN/ ARC-l34 modulation level.

SCOPE OUTPUT jack

Provides a connection from the output of a detector circuit in

maintenance kit to an oscilloscope, permitting the AN/ARC-134

modulation to be observed.

AVC GROUNDED switch (maintenance kit modified)

When set to AVC GROUNDED, disables the AVC circuit of the

AN/ARC-134.

Used to monitor the input current to the AN/ARC-134 under test.

0-10 A ammeter (maintenance kit modified)

When set to position 3 and PTT switch on U-94A/U connector is

Transmit-interphone selector, a six-position rotary

switch (maintenance kit modified)

depressed. applies audio from the H-101A/U microphone through

the preamplifier and amplifier of the intercom control to the trans-

mitter of the AN/ARC-134 under test. Also receiver audio to amps

and headset.

Adjusts volume of the intercom control amplifier

Provides connection for Headset-Microphone H-101A/U. Provides

PTT switch for keying the transmitter of the AN/ARC-134.

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