Countermeasures Control.

TM 32-5865-218-24&P

Contacts 2 and 4 receive lamp voltage from terminal stud El. Switch

S2 is an alternate-action, pushbutton switch/indicator. When switch

S2 is pressed, the C and NO contacts of A close to connect ground

from connector pin J1-N to the lamp C contact. The RCDR ON lamp

lights and the C and NO contacts of A close to connect the 115 V ac

to external system equipment at connector pin J1-D. When switch S2

is restored, the C and NO contacts are open and the lamp is off.

d. CSL BRT Potentiometer R1A. External system equipment

applies lamp voltage to connector pin J1-V. CSL BRT potentiometer

R1A varies the output to external equipment at connector pin J1-X.

EQPT BRT Potentiometer R1B. External system equipment

applies lamp voltage and ground to connector pins J1-S and J1-U.

EQPT BRT potentiometer R1B varies the output to external equipment at

connector pin J1-T.

Interlock Jumpers. The interlock circuit originates at the

external ac line. The 115 V ac ground and 115 V ac neutral

potentials are routed through the ECM panel indicator and external

equipments in the system. The ECM panel indicator interlock circuit

consists of jumpers between connector pins J1-C and J1-F, J1-B and

J1-E. The ground interlock jumper also connects to the cable shield.

If connector J1 is removed, the interlock circuit is opened, and the

external units cannot operate.

3-4. Countermeasures Control. Refer to figure FO-2. The

countermeasures control contains indicator circuit card assembly

(CCA) A3, voltage regulator A1, RF coaxial switch S1, and circuit

breaker CB1. In addition, throuqh-wiring connections are provided

between external system equipments. These connections (see table

3-1) pass audio and control signals that perform no function within

a. Indicator CCA A3. Refer to figure FO-3. The indicator CCA

conditions system audio signals and monitors plain text and radio

control signals. It also provides control outputs to external system

equipment. In addition, the indicator CCA contains a control circuit

that adjusts the brightness of front panel lamps on external system

equipment.

(1) Audio Signal Conditioning Circuits. As shown in figure

3-1, the XMTR AUDIO No. 2 (RCDR) input at connector pin J2-A passes

to the primary winding of transformer T1. The primary winding also

receives the audio return inputs at connector pins J6-P and J6-X

through terminal board connections TB1-17 and TB1-19. The secondary

winding of transformer T1 passes the audio signal through connector

pins J6-G and J6-H to external system equipment.